Who should I go with?

So I was dating this guy for 2 years and we broke up about 3 months ago. I was kind of glad because he treated me like garbage, he would call me stupid and a slut and things like that everyday. So I started talking to this new guy and I started to like him a lot and he likes me too. He's a lot better than my ex, he respects me and makes me happier, hes just better overall, I really like this guy and ive lost feelings for my ex. Now my ex comes back and says he's going to be different and better and that the new guy is worse. My ex is telling me to stay away from the new guy and the new guy is telling me to stay away from my ex. Me and my ex have a lot of history but the new guy and me just get along so much better. My heart and mind are telling me 2 different things. What should I do?