Sometimes, when someone loses someone (be it a friend, a family member, or a lover), they also feel like the very ground under their feet is nonexistent. Not being human does not make grief any different. Not being human and having already seen so many deaths, so many lifes wasted, and so many people lost to him, makes his grief much worse than it should.
He was able to overcome the loss of his planet, the loss of his entire race, the loss of Rose, the loss of the life, the human life, he could have had as John Smith, the loss of Martha, the loss of Donna, and the loss of every single being he could not save. But after going through all of this, he could not cope with the fact that he would not be able to see his best friends again.
The Ponds. Amy and Rory Pond were forever lost to him. Without being able to visit, to speak, or even watch over them. He was depressed. He did not think there was anything, in the whole universe, that could shake him out of his stupor.
Well, everybody knows that, although brilliant, even the Doctor is prone to make a few mistakes. Let's just be glad he has two hearts, because he most certainly is in for a heart attack.
He could hear the storm that was poiring down outside of the Tardis, but could not bring himself to care. He did not particularly dislike storms, but he thought that the rain was worsening his already gloomy mood. Picking himself up from the comfortable couch he had been laid on in the last three hours (or had it been more?), he decided to park somewhere else, maybe somewhere sunny. After some deliberation, he decided to go on vacation. He really needed one, to take his mind off of things. Little did he know that, by being he Doctor, he could not afford a vacation without something happenning.
Oblivious to the events that were being set into motion, he arranged the controls to take him to the Hawaii.
While the Doctor was parking the Tardis somewhere safe within a resort hotel, there was a man watching him. A man who literally could not die, Captain Jack Harkness. Jack grinned like the cat who ate the canary, a smug expression on his handsome face. He chuckled when the Doctor fumbled with the key, and let it accidentally drop to the sand. Deciding that it was a great entrance, he sped up, picked up the key, and when the Doctor looked up, to thank whoever it was, Jack kissed him soundly on the lips. After a few moments in which the poor Gallifreyan was trying to make sense of the situation, Jack spoke:
"Hey there, old man! Thought you would never come here, I'm waiting for you since well... since"
The Doctor, confused, asked:
"How did you know I would come here?"
"C'mon man, that's not the important part, you're making the wrong question." Answered Jack, still looking like a smug cat.
"What? Oi! I'm the one that makes riddles, I'm the one that's funny, not you." He replied, looking annoyed.
Jack got a pensive look on his face, then decided to ask:
"If you are the one that's funny, who am I?"
This time, the Doctor was the one who looked smug.
"Why, you re the pervert, of course." At Jack's sour expression, he laughed loudly, while the other pouted like a toddler.
"Ok then, if I'm just a disposable pervert, I'll go away and never let you know what I came here to tell you, you ungrateful alien!" He said, making dramatic gestures and faces.
The Doctor sighed, and decided to cut the argument short.
"Just say it, Jack. I know you are dying (they both snickered at his non intended pun) to tell me. Say it."
Jack pouted even more, and said dejectedly:
"You are no fun. Alright, I'll tell you, but only because I'm curious of your reaction." At the Doctor's impacient expression, he finally told him what he had been waiting to say for nearly 2 weeks. "You are not alone" Seeing that his friend still had a dumbfounded expression on his face, he elaborated. "You are not the only Time Lord alive anymore. I found another one. She has been on Earth for quite a long time now, I wonder how you two never crossed paths." He stopped rambling when he realized the Doctor was staring into space, slightly shaking. "Doc? Are you alright? Doc!" After not getting any reaction, he shouted. "Doctor!"
Finally snapping out of his trance, the Doctor shook Jack by the shoulders, asking a lot of questions that the man could not understand. He took the Doctor's hands from his shoulders, and told him calmly that all of his questions should be answered soon. After calming him down, both of them entered the Tardis with the intention of going to Torchwood, when the Doctor suddenlly stopped and asked Jack the most important question he had made in quite a while:
"What did she say her name was?"
Jack, grinning from ear to ear, replied:
"Temptation. And what a fitting name that is... The things I would do to that body if only she gave me a little chance..." He sighed, clearly daydreaming, while the Doctor just looked to him, in shock.
"Did you really just say that her name is Temptation?" Jack, looking at te Doctor as if he was dumb, replied.
"That I did, what's the matter? You look a little green for an alien..."
The Doctor stepped back, grinning like a madman and ran to the controls adjusting the course to Torchwood.
"Green? I'm bloody fabulous, I'm feeling great, brilliant even! Now off we go, to Torchwood! Alons-y!"
Jack, frowning, asked:
"Ok, I get it, she is hot and beautiful and I want to just bend her over a desk and pound into her, but I don't know why you're so happy. I mean, you always act as if you are assexual."
The Doctor, ignoring his jabs, but narrowing his eyes at Jack's sexual interest in the Time Lady, just replied simply:
"She's my wife."