I've often wondered what must have been going through John's head from the time he found out that Mary had shot Sherlock to the end of The Lying Detective.

I would never want to excuse anything he did to Sherlock after Mary's death, it was wrong. Sherlock would have every right not to forgive him. But I'm glad that he did.

This diary is my attempt to create the confusion, hurt, grief and guilt John must have been feeling over those months.

I don't normally write to myself, I normally write to the world on a blog. Ella, my therapist, told me years ago that putting things in writing would help me get things straight in my head and she was right to a certain extent. But there are some things you never want the world to know. There are some things you don't even want the people closest to you to know. So here I am, writing to myself, writing a diary.

I thought life was going well. Sherlock was alive and I'd met the perfect woman. I'd married the perfect woman. Or so I thought. Then Sherlock was shot. He nearly died. Correction, he did die. His heart stopped while he was on the operating table. But he survived and I thought the worst was behind me. How wrong I was.

I've just found out that I married an assassin. A murderer for hire. She tells me that if I know all the facts I won't love her any more. She even gave me a flash drive with all the horrible details on to prove it. I'm not sure I love her anymore anyway. She lied to me. About everything. Her name, who she was, her whole life story, just one big lie. And I was taken in. I believed her. What a fucking idiot I am.

Oh and guess what, the person who shot Sherlock, that was her too. She stood in front of my best friend, looked him in the eye and pulled the trigger. How could she do that? He was making no threat to her life in fact he wanted to help her. She knew I'd lost him once already and the effect that had on me but still she didn't think twice about it.

Now Sherlock is telling me that it's OK. That she never meant to kill him, in fact she aimed so she'd miss all his vital organs and then she phoned for an ambulance. He tells me I can trust her. Yeah, right. I can trust a woman who has lied to me from the day I met her and is capable of shooting another human being just because he was in the way at the time. I don't care if Sherlock thinks her aim was that good that she planned for him to survive, the point is she couldn't know he would. He nearly didn't. What normal person can do that?

So now I'm back at the hospital, waiting to see if Sherlock is ok. He decided to run around London getting Mary to admit to me what she'd done. He's now opened up his wounds and is bleeding internally. The cock!

I sent Mary home. I can't stand to even look at her right now. And I can't go home, I'm not even sure I have a home. How can I go and play happy families with her after all that she's done? But she is carrying my child. Sherlock seems to have forgiven her and moved on. I just can't do that. It's not that easy. How do I just put all this behind me? How? Oh god it's all such a mess and I'm not sure that I will ever work this out no matter how much I write to myself.

OK so I haven't really taken to this diary writing thing. It didn't work when I tried it the first time. I know I should have given it more of a chance. Ella's right, sometimes I just expect things to happen all at once and in reality they don't. So here I am again trying to work out what the hell I'm supposed to do. Do I stay with this woman who's supposed to by my wife, the mother of my daughter or not?

It's been months since I found out about her shooting Sherlock and I must admit I've been finding it hard to even talk to her let alone forgive her in anyway. But maybe I'm being too hard on her. Maybe I've not even really tried to forgive her.

Sherlock has definitely forgiven her and moved on. He seems to have a better relationship with Mary at the moment than I do. I know she's had an unusual life. Being an assassin, having people wanting to kill you all the time must give you a slightly strange view of the world I guess. I suppose I can understand that if you were trying to put that life behind you, you'd have to invent a whole new person to do it. And I guess that having done that it would be difficult to ever tell anyone the truth no matter how much you loved them. But I'm just finding things hard. No matter how much I reason with myself, no matter how much, logically, I understand why she lied for some reason the moment I look at her all that vanishes and all I feel is anger.

Why does my life have to be so hard? Was it wrong to just want a loving wife and family? Love. That's the other question I guess, do I still love her? Yes. Unfortunately the answer to that is yes. If I didn't this would be so much easier. I would be able to just walk away but I can't seem to do that.

Then there's the baby. What would I do about the baby? She's my flesh and blood. How could I just walk away from her? If I left Mary over this how hard would it be to have contact with my daughter? Mary would probably feel the need to leave this place, reinvent herself again and no doubt she'd take our daughter with her. I'd never see my child.

Jesus Christ I certainly know how to make my life complicated. A high functioning sociopath for a best friend and an ex-assassin for a wife, only John Watson could manage that. I'm an idiot, a total idiot and I have no idea how to move forward and make this work.

Today I'm writing to myself sat upstairs at Sherlock's parent's house while Sherlock, his relatives and my heavily pregnant wife sit downstairs playing happy families. Can you believe it? This feels so weird. I think this is some sort of plan by Sherlock to help me and Mary see what happily married life should be like. His parents are wonderful together. They look so happy even after all these years. It's hard to believe I couldn't even manage 6 months before it got screwed up.

I've thought long and hard about this, in fact really I've thought of nothing else for months and I'm not getting any further forward. I don't think there is an easy answer. I don't think there is a right or wrong answer so I'm just going to have to make a decision and live with it.

But what decision should I make? Well what do I know? I know that Mary is going to have our child in just a few months, a baby girl. That thought makes me happy. I'm not sure I could live without her. Sherlock, my best friend and the person Mary nearly killed has forgiven her completely and seems to enjoy her company. So why can't I? Maybe I'm just being too hard on her. Maybe I'm being unreasonable. Maybe I should be a bit more understanding and move on. I do still love her, well I think I do. I certainly still have quite strong feelings for her. Maybe not as strong as before but that doesn't mean I couldn't get them back. Right?

I still have the flash drive. I've never looked at it. Can't bring myself to do it. Perhaps that should tell me something. If I really didn't care about Mary I would have looked at it by now. It wouldn't matter what I'd find out because it couldn't destroy feelings that weren't there. I guess that proves I do still love her in a way.

Right that's it then. I'm not sure if this is the right thing to do but I'm going to go downstairs and tell her that I want us to be a family. A proper family.

Oh God Sherlock, what on earth did you think you were doing? My best friend just killed a man to protect the identity of my wife. The woman who tried to kill him.

What am I supposed to do? I should have seen it coming, I should have stopped him. He's thrown his life away for me and Mary and I'm really not sure we deserve it. I've only just managed to have a reasonable conversation with her for the first time in months and yet he thinks our marriage is worth giving away his freedom for. How can I live with this? How can I possibly help him?

What a strange day. When today started I thought I was going to be saying goodbye to Sherlock Holmes forever. Mycroft had managed to pull strings and get Sherlock some sort of exile rather than a trial and a prison sentence. The things that man can do.

So I stood and said my goodbyes at the airfield only to have Sherlock return a few minutes later as high as a kite because Moriarty is back on the scene. How? He shot himself. How can he be back? According to Sherlock he is dead so I can honestly say that I have no idea what's going on. Still I have no doubt that Mycroft can sort something out so that Sherlock can return to Baker Street.

Maybe, just maybe life can start getting back to normal now.

I had thought that once I'd decided whether to stay with Mary or not I'd never need this stupid diary again. I guess that's not the case. I can't talk to her about how I feel, I'm not sure I even know how I feel. I can't tell my therapist without telling her that my wife is an ex assassin who shot my best friend and I can't talk to Sherlock. I'm not sure how much human emotion he could stand. To him it's logical. Forgiving Mary was logical. But no matter how hard I try, being that logical about everything she did is not easy. There are days when I find it really hard to just act like nothing happened. Days when no matter how hard I try to forget, when I look at her it's all I can think of.

Then there's Rosie. Our gorgeous, perfect little baby. She is those things. When I look at her I feel love like I never knew existed. But she's also a little devil. She demands all your time and patience, deprives you of sleep and you still have to try and function like a normal human being the next day by going to work and earning money to pay the bills. Being a new parent is definitely not easy. But that bit of my life I wouldn't want to change for the world.

That's not to say I really want to change any of it but sometimes I find it hard. I love Mary, I do and obviously my feelings for Sherlock have never changed, he will always be my best friend but sometimes they make me feel like an outsider. I mean, they are both much cleverer than I am, Mary has skills that even as a soldier I could never hope to match and Sherlock finds those skills useful. I understand that but it doesn't make me feel any better. For God's sake I'm jealous of my own wife being better than I am. If I'm honest with myself I guess I'm worried that neither of them really needs me anymore. I have no use. Neither of them would miss me if I wasn't here. That sounds stupid, it is stupid but it's still how I feel sometimes.

Oh God what have I done. I'm an idiot. A fucking idiot. Mary has nothing on me when it comes to screwing things up. So what if I was feeling a bit alone, a bit left out, a bit unneeded. So what if Mary lied in the past does that really justify what I did? No it doesn't. I forgave her for that. I told her we'd put it behind us. There is never any excuse for cheating. And that's what I did. I cheated on my wife.

I don't know why I text her. She was just some random woman on the bus. So she smiled, she said I had nice eyes. Big deal. Why didn't I just throw her number away like I first intended to? For some stupid reason I just couldn't do it. For some stupid reason I thought texting her would be OK. But it isn't is it? If it was really alright I wouldn't be feeling so damn guilty.

Just because I ended it before it went any further than texting doesn't excuse what I did. I cheated on my wife while she was looking after our baby. How low can you get John Watson? You bastard!

To make it worse with all her past coming out like it has she feels like she should be the one apologising. For the secrets, for running off to protect our daughter. She seems to think I'm this perfect man and I'm so far from that. She really couldn't be more wrong about me.

I'm going to have to tell her. I can't live with myself, live with her thinking I'm something I'm not. All that time I debated whether our marriage would work after all her lies and it's me that puts the final nail in the coffin.

This could be it. I may never see my wife or daughter again. And you know what, I deserve it after what I've done.

I don't know why I'm writing this. What do I hope to achieve? My wife is dead. What do I think a few lines on a piece of paper are going to do? They're hardly going to bring her back. Bring me back my wife, bring Rosie back her mother.

Rosie, what am I going to do about Rosie? I'm all she has left now. This life that I loved, that Mary loved, full of danger and excitement, it took away her mother. I can't let it take away her father too. That's it, I'm going to have to grow up, be a responsible adult for once in my life. Be a doctor, a GP and be happy with that. No more chasing villains all over London. It's not safe, not safe for my daughter and I promised Mary I would look after her.

Then there's Sherlock. He promised he'd protect Mary and he didn't. I wasn't there, I couldn't do it and he let me down. Let Mary down. I know everyone thinks I should see him and they're probably right but when I see him I just feel so angry. I know I shouldn't but I do. I was Mary's husband, it should have been my job to protect her but I wasn't there so how could I? Besides Sherlock had made a vow, he'd promised he wouldn't let anything happen to her.

And now she's gone. I'm alone, a single parent and I'm not sure I can do this. In fact, who am I kidding, I'm not doing this. I'm failing Rosie every day. Every day other people come round and care for her, Mrs Hudson, Molly, anyone except me, her father. I'm useless.

I'll write a note to Sherlock. Tell him I never want to see him again, that I won't be having anything more to do with him. Then next time he comes round I'll ask whoever is here at the time to give it to him. I can't talk to him. I can't see him. I feel so angry with him right now. I know I shouldn't feel like that but I do. I just can't bring myself to look at him. And besides he's right I'm addicted to danger, the thrill of the cases. If I see him I'm scared I'll weaken, be drawn back into that life and I can't let that happen. I just can't. For Rosie's sake I can't get myself killed. She needs at least one parent, maybe even one as pathetic as me.

Jesus Christ John Watson what have you become? A monster, that's what. A horrible excuse for a human being.

Today I beat my best friend. I know he was wielding a scalpel but trust me that's no excuse. The press might be hailing me as some kind of hero for saving Culverton Smith but the truth is I'd disarmed him, he was no longer a threat and then I carried on hitting him and kicking him for no reason. Even when he looked at me with all that hurt in his eyes saying I was entitled, he'd killed my wife, I told him yes he had. I know that's not true. I've always known that's not true. So why have I let him believe it? Why have I behaved like I believe it? Because I wanted it to be true, that's why. I wanted it to be his fault because then it stopped being mine.

And after I'd treated him so badly, do you know what I found out? I found out that this whole drug taking episode was a plan to put himself in danger so that I would rescue him because my dead wife told him that's what I'd need to do to get over her death. He risked his life to save me and I really don't deserve it. If Mrs Hudson hadn't shown me that recording Mary made I might never have gone back to that hospital and he'd have died. He'd have been killed and it would have been my fault. I put him in that hospital by beating him and then I was going to leave him there to die. What sort of a person does that? I'm no better than the criminals we chase.

Well Sherlock is getting a lot better. I have visited him a few times in the hospital but only for a couple of minutes. I use my daughter as an excuse not to have to spend time with him. How awful is that? He must know what I'm doing. He's not an idiot and he's always been able to read me like a book. But after everything I've done I can't face him. I can't look at him knowing that I'm responsible for the state he's in.

Tomorrow he gets discharged and we've all agreed to take shifts to sit with him, make sure he stays off the drugs. I have no idea how I'm going to sit with him for hours like I'm his friend. How can I ever call myself his friend again? Friends don't treat each other the way I've treated Sherlock. I have no idea how I became this person. I'm so far from the person I wanted to be that I can't even remember who he was. I hate what I've become. John Watson, army doctor, Captain in the Fifth Northumberland Fusiliers and complete and utter dick.

Sherlock Holmes will never cease to amaze me. I went to do my shift and to be honest I didn't want to be there. I felt uncomfortable in his presence after everything I'd done to him. The guilt was overwhelming. I just wanted to escape if I'm honest and I was going to. I made my excuses saying I needed to pick up Rosie. That was a lie, I'd arranged for her to be looked after until later in the evening but I couldn't bear to keep looking at the damage I'd done to him. I was going to get my coat when he asked if I was alright. I snapped at him. Even after everything I knew I still snapped at him. I did manage to finally tell him that Mary's death wasn't his fault but I still didn't apologise.

The only thing that stopped me from leaving was a text from The Woman. Can you believe it? She's still alive and still texting Sherlock. Talking about her led onto other things and before I knew it I was stood in the middle of 221b confessing my sins to my dead wife, well the image of her in my head anyway. I needed to get it off my chest I guess. Not that it really counts if the person that needs to hear it isn't there.

And after all that, after everything I'd done to him, after finding out that I'd cheated on my dead wife, what does Sherlock do? Does he have a go at me like I deserve? Tell me what a total bastard I've become? No. He comfort's me. Tells me I'm only human after all and it was only texting. And then we go and meet Molly for cake.

I don't deserve this. I don't deserve any of this. I've let everyone down. I've let Rosie down, I've let Molly down, I've let Mrs Hudson down, but most of all I've let Sherlock down and he still wants to be my best friend.

It should have been me that died. I should never have let Mary go to that aquarium without me. I should have made her wait for the babysitter and gone to Sherlock. Then it would have been me that needed to protect him, that's my job after all. It was me that let Sherlock down not the other way around. I wasn't there when I was needed and Mary died because of it. It was me who let her down. I couldn't even protect my own wife. What a useless excuse for a soldier I am.

And since then? Well, since then I've continued to let everyone down. I couldn't even look after my own daughter. I've palmed her off on everyone else. She lost her mother for God's sake but still I left her in everyone else's care. Mary wouldn't have done that. Mary would have cared for our daughter. She wouldn't have taken all her grief out on others like I have. It should have been me. It would have been better for everyone if it had been me.

But it wasn't. So I guess I'm going to have to learn to live with that. Learn to live up to the faith my friends have placed in me. Learn to accept that I'm here and Mary isn't.

I'll start tomorrow by apologising to Sherlock, for everything, blaming him, shutting him out and the beating. I definitely need to apologise for the beating. He just seems to forgive everything. He forgave Mary for shooting him and he's forgiven me for beating him. He deserves better, much better than me really. But I will try my best to make things right. I have to. Maybe then I can get back to being the John Watson I wanted to be.

Today I apologised to Sherlock. It was one of the hardest things I have ever had to do in my life. He tried to tell me that I didn't have to, that it was fine. But it wasn't fine. I had to do it. I needed him to understand that I know everything I put him through was wrong, was unacceptable and unforgiveable. I needed him to understand that I will do everything I can to be the man he thinks I am, the man they all think I am rather than the one I know I have become.

I think Sherlock found it hard too, sitting quietly and listening to me while I poured my heart out. Most of the time I didn't look at him, I couldn't. I knew that if I did I wouldn't be able to continue. Then when I'd finished there was this uncomfortable silence and I thought that maybe Sherlock wasn't ready to forgive me after all. That he'd at last realised that he deserved better and that I wasn't a friend at all.

Eventually, I got up the courage to look at him, look him in the eye like a man and when I did I saw nothing but love and understanding. It's hard to believe that I once called him a machine, I could not have been more wrong. I will never forget the kindness he showed me again today, I don't mind admitting it brought a tear to my eye.

By the time I'd finished my shift with him things were a little easier between us. I felt a little more relaxed in his company. And when Mrs Hudson came to take over I took the opportunity to apologise to her too. She just smiled and hugged me. How can these people be so forgiving after everything I've done? I don't think I'll ever quite understand it.

I know I have a few more apologies to make and I will make them. Hopefully then I can start to be a better person, a better father and a better friend.