I feel stuck!

I’ve been with this guy almost a year, we’ve been on and off due to him cheating but still tried to work it out because neither of us wanted it to end. I even admitted to being with another guy while we were apart so the slate was clean. Things were going okay but then he just started drinking every night, going out and ignoring me, and going with girls he knows I don’t like. Every time I try to leave he just begs me to stay and I always cave. I don’t know how to get out of it. I miscarried and few weeks back and he decided to breakup with me just days after. Now he’s trying to come back into my life and something in me can’t seem to let him go. I stupidly agreed to let him come over and he told me he realized what he did was wrong and He promised all the girls would be blocked by tonight but he also got super dry after leaving my house this morning. How do I break that stupid attachment!!!