I really hope someone else will write some post-engagement fluff. I feel like this wasn't very good but I had to write it because I have a lot of feelings right now. Oh my god, that episode! Ah, I'm still emotional. I've already watched the proposal like 10 times, because it's perfect. Anyway, I'm sorry if this was terrible. It was something I had to write. Oh and the title is based off the song that played during the closing scene of the episode, Let Your Heart Hold Fast by Fort Atlantic. And let's all be thankful because our couple is finally engaged! YAAAAAY!

After they finally leave the WWN roof, which admittedly takes awhile (it was already Robin's favorite place in the City, now it's still her favorite place for a whole other slew of reasons), they go back to her place. More specifically, they go back to her bedroom where they spend the next couple of hours in a post-engagement glow. And it's amazing, completely wonderful, blissful, any other happy adjective she can think of. But there's a nagging voice at the back of her head that keeps telling her they need to talk. Okay, they really do need to talk but not right now.

Hours later after several rounds of engagement sex, some sleep and then some more sex; she finally brings it up. She pulls his shirt on because, let's face it, if they tried to have the conversation without it on very little talking would actually get done.

"Okay, we need to talk." She says semi-seriously but with a smile still playing at her lips because she can't wipe the smile off anyway.

"About how sexy you look in my shirt? Yeah, we do." She laughs as he pulls her in for a kiss indulging in the moment. "Alright," he concedes moving away from her. "What do we need to talk about?"

"First off, I want to apologize for last November." Barney quickly shakes his head, but she silences him. "I have to get this out. I didn't realize how serious you were about us and I should have."

"No, you shouldn't have. I didn't tell you how I felt and I couldn't have expected you to know that. I'll admit I was angry at first, but then I realized it was partly my fault-" Barney sighs and Robin reaches out rubbing her hand up and down his arm.

"It's in the past now. I just wanted you to know that-" She pauses trying to collect her thoughts and Barney smiles encouragingly at her. "That me deciding not to be with you that night had nothing to do with my feelings for you. I wasn't ready yet, but I am now."

"Me too." He nods smiling widely and she can't help but smile back just as wide. "You know we're going to have to tell everyone soon."

"Let's stay in the bubble a little longer?" She pleads. "Besides Ted knows."

"How much?"

"That it went well, but not that we're engaged." Robin says with a shrug. That isn't something you can tell someone through a casual text.

"No one is going to be expecting that." He says with a small laugh.

"I wasn't expecting that." She admits.

"I know, that was the point, shock you into a yes."

"You didn't shock me into a yes." She mumbles and he raises an eyebrow. "I said yes because I love you." And she realizes it's the first time either one of them has said it all night. Of course it was implied when they decided to get married, but neither one of them actually said it. Barney's eyes soften and he pulls her closer.

"I love you too." She leans into him reveling in the moment because she knows she'll have to interrupt it again.

"Barney, I have something to tell you." She says surprisingly serious. He nods and sits up. She can feel the jitters in her stomach because there is a reason Barney is only finding out about her infertility now. She was always most nervous of his reaction, but she can't avoid it anymore. She has to tell him. "I'm infertile." She blurts it out before she has time to think of a more eloquent way to word it. She can't bring herself to look at him and she braces herself for his reaction.

"What?" He asks and she plays with the buttons on his shirt.

"I can't have children." She tries to keep her voice calm, but she can tell it's shaking a little bit. Barney reaches over and takes her hand squeezing it in his.

"I could care less about whether you can have kids. All I want is you," he smiles. "How long have you known?"

"Last Christmas," she informs him and she knows that will explain it all. She's sure he remembers last Christmas just as well as she does.

"Why didn't you tell me sooner?" He asks quietly and she can hear the concern in her voice. She knows she was an absolute mess last year and she really doesn't want to relive that time in her life.

"I was scared of your reaction. I was worried that it would mean we were over for good." She shrugs not wanting to put too much weight on her words. She wants to tell him about the kids she imagined, their kids. That's really why she had been so upset. Not because she was losing the opportunity to have children in general, but because she was never going to have them with Barney. And she still doesn't want kids, but sometimes she thinks of those imaginary children, that life would not have been too bad. But that's not going to be her reality and she's finally okay with that.

"Well, it doesn't. I still want to marry you." She doesn't think she'll ever get tired of hearing that. She remembers hesitantly accepting Kevin's proposal and how different that was compared to the easiness with which she said yes to Barney. And she understands what Ted has been blabbering on about all these years. She finally gets why his endless search to find the one is so important to him. She curls back into Barney and resolves to help Ted find her. After all, she owes it to him. She never would have ended up here without him. "Okay, so breakfast and then time to face the music?" Robin laughs and rolls her eyes.

"You act like it's a death sentence."

"I'm more concerned for you than me. As soon as we tell Lily she's going to make you start planning the wedding." He smirks looking down at her. "The only thing I have to do is ask Ted to be my best man."

"No!" Robin protests and immediately sits up. "I already asked Ted to be my best man two years ago."

"What?! You were single two years ago."

"I know, I was just planning ahead."

"How do we decide who gets him?" Barney asks and Robin is silent for a few seconds.

"You can have Ted."

"Really?" Robin nods.

"He's your best friend. And I can ask Lily to be my maid of honor. Besides Ted will still be there if I need him." Barney should have Ted as his best man.

"We could share him if you want?" Barney suggests glancing over at her and she raises an eyebrow at him.

"Dealing with the two of us on our wedding day? Do you think one person can handle that?" She asks with a laugh and he soon joins in.

"You think we'll be that difficult?"

"Normal people are nervous on their wedding day."

"Good point. Okay, so I'll have Ted and you'll have Lily. Between the two of them we can get down the aisle."

"I think so." They both laugh.

"Alright, it's time to leave our bubble and tell everyone." Barney says with a sigh.

"I hope you know you're planning with me and Lily. I'm not letting you out of that. You can't make me do it alone."

"I will." He promises laughing. "As long as you promise you'll sing a Robin Sparkles' song at the reception."

"Nope. Definitely not." She shakes her head. "Condition not accepted."

"But Sandcastles in the Sand is our song." Barney whines.

"Nope."

"What if I sing with you?"

"You will never talk me into it."

"Dammit." He curses and she smiles apologetically turning to kiss him. "I knew it was a long shot anyway." He murmurs against her lips.