Doesn't matter what you do. It will always be your fault. Always. You're being quiet? - you're giving them the "silent treatment". You smile and pretend nothing's happened? - you're being "condescending" or not repentant enough. You ask for some space to think things over? - you're being passive aggressive and distant. You don't have any control over conversations, it's like whenever he's in one of his moods you get stuck with that duty of being a super-human with super-human self-control where all you try to do is get to the bottom of the problem and fix it and he just wants to watch you lose your shit. He behaves like a five year old, making faces at you, intentionally twisting your every word to make it sound obnoxious or ridiculous, bringing up every little thing you did wrong since you've met, etc. Trying to derail the conversation and win by merely exhausting you with endless repetitions and circular reasoning. Notice how he's always calm and almost smiling when you're slowly losing your mind - it's exactly what he wants and he celebrates proving to you, yet again, how crazy you are.
Years after years of this conditioning you start to believe this shit. One day you wake up ashamed of just existing. Every emotion, every concern, every legitimate reaction you have, he's embedded an ugly caricature of it in your head. You wonder how you could ever even believe anyone would want to be with you because every day your every single flaw is pointed out, magnified and you're being made to make up for it. You can't get undressed without him enumerating every scar, every ingrown hair, every discolored patch of skin - every day, year after year, he doesn't "get used" to it, he just keeps reciting the same list, adding to it occasionally. Eventually you don't see yourself as anything else but this list. You freak out when a stranger flirts with you, when people compliment how you look, because now the only kind of attention you know is attention to your flaws.
Your life is being turned into a grotesque parody of itself. You forget what it's like to want to compromise because even when you back down almost immediately, you have to go through the tedious process of convincing him you really mean it, - while he's hung up on your initial negative reaction or refusal - and he always gets his way. Not only you're forced into doing what you hate, you have to practically beg him to let you. You get more jumpy and bitter because there's literally no safe place for you because every single aspect of your relationship is controlled by his moods. You never thought you could hate people before, you chose to minimize conflict and simply fade away when you didn't like someone - but now you catch yourself wishing all sorts of evil things on him and feel like shit for it. He brings out the worst in you so he can justify his own behavior - see, at least I'm not crazy, I was only trying to explain myself and my favorite - _I thought I had a RIGHT to express my disappointment! Eventually you're exhausted to the point of not even wanting to leave because what's the point? - the hell is only going to repeat itself with every new person and you just can't risk it. At least this is the enemy you know, you've learned how to navigate parts of it, you're just happy to be left alone from time to time. As long as you're always on alert and keep the important shit to yourself - don't let him know how you feel, don't let him close to the things you like cause he will ruin them for you or try to take them away, don't reveal the things you hate because you'll be forced to experience them on a regular basis because he sees it as a challenge. If you're going through all this for years and still manage to stay kind and positive, you're either retarded or completely detached emotionally. People can go through years of persecution, torture, poverty, etc. and remain intact. But when you attack them on such intimate personal level there's no chance they will come out unscathed.
tl:dr - fuck everything about BPDs. Not just because they hurt everything around them, they contaminate everything they touch with their poison and misery.