1. At some point pre-war, Bucky was raped: maybe once, maybe by a gang, maybe repeatedly by someone who had power over him. He never told anyone, and he spent years blaming himself, letting it eat him up from the inside.
2. Post-Winter Soldier, Bucky and Steve begin a romantic relationship, and Steve guesses Bucky has been raped. And the truth is Hydra didn't sexually abuse him, but Bucky just... goes with it, and instead tells the story of his pre-war rape as though it had been perpetrated during his captivity. Then he eats up all the reassurances that it wasn't his fault, he didn't know he could fight back, etc.
The problem is that despite how much Bucky needs these reassurances, he believes that Steve is only exculpating him because he thinks Hydra did it; Bucky fears that if Steve knew the truth, that no brainwashing or torture was involved, he'd blame Bucky just as much as Bucky blames himself. But he can't stop talking about it and he can't stop lying, because it feels SO GOOD to finally be told it wasn't his fault. And then it feels worse because he doesn't deserve to feel good -- and so it goes.
3. self-hatred. pain. drama
+ if Steve is part of the reason Bucky blames himself. Like he saw something and misinterpreted it; what was really evidence of the rape, Steve understands as Bucky having been out drinking with/buddying up to/having consensual sex with some bully. So he makes a snide remark and forgets about it. Only Bucky doesn't know that Steve misunderstood what he saw. Or something!
+ if Bucky confesses but along the lines of "I lied, Hydra never raped me" so Steve is angry and STILL doesn't understand
Bucky lies about being raped (sort of)
2. Post-Winter Soldier, Bucky and Steve begin a romantic relationship, and Steve guesses Bucky has been raped. And the truth is Hydra didn't sexually abuse him, but Bucky just... goes with it, and instead tells the story of his pre-war rape as though it had been perpetrated during his captivity. Then he eats up all the reassurances that it wasn't his fault, he didn't know he could fight back, etc.
The problem is that despite how much Bucky needs these reassurances, he believes that Steve is only exculpating him because he thinks Hydra did it; Bucky fears that if Steve knew the truth, that no brainwashing or torture was involved, he'd blame Bucky just as much as Bucky blames himself. But he can't stop talking about it and he can't stop lying, because it feels SO GOOD to finally be told it wasn't his fault. And then it feels worse because he doesn't deserve to feel good -- and so it goes.
3. self-hatred. pain. drama
+ if Steve is part of the reason Bucky blames himself. Like he saw something and misinterpreted it; what was really evidence of the rape, Steve understands as Bucky having been out drinking with/buddying up to/having consensual sex with some bully. So he makes a snide remark and forgets about it. Only Bucky doesn't know that Steve misunderstood what he saw. Or something!
+ if Bucky confesses but along the lines of "I lied, Hydra never raped me" so Steve is angry and STILL doesn't understand