Cheating life changing.

So my boyfriend of 3 years since I knew as a teenager has blamed me for things he is doing. I am confused often, until I remember his tendencies. I am pregnant and I deal with a lot, him coming home drunk everyday after work, dealing with an asshole and an instagter, the worst of all. I leave from the house and walk in the snow until he sobers. I am back, take a hot shower and girls are still texting him. Hours I waited for him to just be asleep. I'm thinking of leaving and not having kids. He says I am nothing, but I do not believe that. I should not, I will not, but I am very low