Anxiety due to relationship issues.

Dating this guy for 9yrs now he had way too many ex gf's who dint stay in his past which got alot fights between us he hid the fact that he met his ex and got physical abusive when I confronted him. He's been broke most of these years finally when he got a good job he went ahead and started flirting with this girl in his office who said she likes him and he wanted to take a break from me after 7yrs saying we have issues instead of telling he wants to be with her so that flirting ended when he found out she was doing it for a bet no feelings etc and he asked me to talk to her and tell her he wasn't Interested and that I'm still his gf and he tells me he wasn't Intrested in her and I was making things up when I clearly read all their chats. He's been physically abusive in the past but now inspite of forgiving whatever happened in the past he's screaming and telling me I'm a horrible person who can't trust him we fight everyday and keep patching up only to break up again help!