Just to make it clear, it the hit didn't cause much damage/bruising and etc. It hurt, and wasn't nice, but I was physically ok. 
It all started with the domestic argument, I've got upset with him not helping me around the flat (we live together), I expressed my dissatisfaction with it, which is still, in my opinion, completely fair, giving that we both share one bedroom flat. He pushed me after i said that, I feel that, he does not care about me, when he does some little effort around the house. I got shocked and asked why he would do it, and he said that it's nothing because I was psychologically abusing him for the last half a year and in general I'm never happy. 
I've been depressed and insecure for a quite long time now, and he is aware of it. And he really tries his best to support me, but when we get fights, which is very often lately, it gets out of control. I haven't been diagnosed it with BPD, but a lot of symptoms sound  like me. It's very hard, for both of us , but with the lack of money and time, I can't afford counselling (I live in UK) or more help. Lately, just after my birthday, I've been trying to work on myself, reading self books, singed up for the gym, found DPD skills workbooks online which I was meant to print out. I was trying to push and motivate myself. 
And now I feel just like a piece of worthless shit, I don't even know why I was trying. My illness makes him desperate to the level where he wants to hurt himself and me (even if not intentionally), and I feel so trapped and guilty about everything. 