Heartbreaking | Advice?

My first heartbreak lead me into deep depression. I've been depressed ever since I was younger because my family treated me as if I wasn't loved, which made me hate myself and made me feel like I didn't belong. Imagine sucide thoughts in 5th grade. Even though that has nothing to do with heartbreak (somewhat) it's important. My first true heartbreak made me sick emotionally, mentally and physically. I didn't eat. Sleep. My grades went down. My confidence left. I hated myself. He left me because he wanted freedom and to be with a 15 year girl. (We were both 18). So I'm in college now. And I met someone new. We had sex.. We liked each other and he messed up but I forgave him. (He slept with a 16 year girl and lied about it) And I gave him a second chance and come to found out.. He's been with her this whole weekend and week and told me he gives up on us and that he wants freedom. My ex before did the same thing... And I'm torn. How should I handle this? How can I get over this situation that's reminding me of. Bad time. I feel like I'm not beatuful enough. If expressed enough. Good enough. He even said I acted too much as a girlfriend (we weren't officially together). I cared too me... Is it my fault? And I'm scared that I'll go back to how I was in the past. Can I have some advice?