John and Bob have an ongoing no-strings-attached-but-not-really situationship that started sometime during the first year post-thunderbolts, born out of isolation, pure loneliness and hurt/comfort.
They pretend like it's just sex and neither one will admit it to the other (or themselves) but it's not. Neither one of them really has any healthy connections outside of each other and the team. They realize this during some holiday when Yelena and Alexei are off with Melina and some other widows, and even Ava is off visiting Scott. Both Yelena and Ava offer to stay back so Bob won't be alone, but Walker sheepishly admits that he has no plans either, so they can keep each other company. They spend six months worth of holidays like this. Some are spent genuinely innocently, as purely friends. For others, they stay connected from the time the door clicks closed behind the last person leaving until it creaks open with the first to arrive.
Bob has never felt so loved, even if it's just a situationship. John has a near obsessive need to care for someone, and he seemingly devotes all of his time and energy into making Bob that person. It gets to the point where it's no longer even subtle, and the girls surely would start to notice. Except it stops.
A years worth of softening does more for John than just improve his mental health. It makes him a better father. Olivia feels more and more comfortable having John around their baby. She floats the idea of maybe getting an apartment in NYC. Of course John is ecstatic, but he's still nervous. Is it the right move? He asks Bob for advice and Bob assures him that this would be good for him. He just wants to see John happy, and he knows that being so distant from his son weighs heavily on him. He doesn't really think anything of it.
John and Olivia decide she'll get a 3 month lease to test run things. Bob had never seen John cry happy tears until that moment.
He isn't stupid. Bob knew that John having his son more meant there would be less time for them to hang out, sexually or even otherwise. But he wasn't prepared for it to completely stop. Even when Walker is alone he starts to ignore Bob's advances. By month two, Bob would accept that their thing had just run its course. Except.. every third or fourth time, the wall comes down, and they spend a weekend so nice together that it makes Bob feel like he was silly for ever worrying in the first place.
Still, Bob spirals. He always tries to reel it back. This isn't about him, and he doesn't want to make it about himself and ruin John's reunion. That's selfish. The naive part of Bob's brain (the one he had previously squashed, but John had revived during their year of being FWB), believes that if he says something, it might make John reconsider having Olivia and his son live nearby. John asking his opinion had given him the false impression that he was involved in this at all. It shouldn't be, but it's a massive blow when John finally points out that he isn't.
It's that holiday again and all Bob can think about is how it would be a romantic time for them to "come out". It's the anniversary of the first one they spent together, after all.
All John is thinking about is his son. It's the first holiday he'll get to spend with him since everything happened. Bob doesn't fit into that equation. The tower is no place for a 5 year old, so John spends it at Olivia's apartment.
Yelena insists on staying back, but Bob lies and says he already accepted an invite from John. She's suspicious but chalks it down to tradition. The real reason is because Bob knows that Olivia and the baby are visiting family after the day itself. Spending the actual holiday alone is worth it to Bob if it means having John and the tower to himself in the days following.
Olivia ends up surprising John with a last minute plane ticket and invite to come with them. He's so elated to finally be included that Bob doesn't want to burden him with the weight Bob's feeling for being excluded. So he lies and acts like it's a relief. He was planning on going with Yelena, but didn't want Walker to be alone. Now he can finally go and meet some of the Widows.
Bob doesn't leave his bed the entire time they're gone.
Things like this seem to happen progressively more and more. But it's not like it's just any other person. It's Walker's son. So Bob tries to be understanding, and while doing so misses every sign.
It might have been more obvious that John was wearing his wedding ring if he hadn't been this entire time. Maybe that should have been a sign in itself.
They haven't had sex since before that holiday, but they haven't had a conversation about it either. In Bob's defense, much of the time inbetween had been spent on missions, so there were logical excuses he could make.
It all comes crashing down when Olivia's lease is up. Bob has remained supportive despite his mixed feelings, but it's not exactly hard to hide them because John avoids the topic at all costs. Bob has to practically corner him one day.
It starts with John admitting that he's looking at apartments with them. Bob does not take the hint. Olivia and baby move into the tower temporarily while they search. Bob offers to give up his part of the tower for them, but Walker tells him, like it should have been the most obvious thing in the world, that they'll just be staying in his. Bob still doesn't get it until a week later when he sees them kiss.
tl;dr / the original broader prompt i had in mind:
Bob and John are FWB but at some point Olivia and John decide to try to make things work for their son. Maybe it works out or maybe it doesn't. Either way the ~angst~.
