I really need advice

Before anyone says anything. I genuinely do want to stay with my boyfriend. I don’t wanna break up with him. I do love him with all of my heart. A few months ago I found out he was talking to his ex for the first few months of our relationship and cheating on me. He knocked me up after a one night stand. He told her how much he didn’t love me and he still loved her and how I was crazy and literally secrets about my childhood I trusted him with. And my hearts really been broken since. I’ve tried to work through this...He admitted to it. He doesn’t hide anything from me. He’s an angel now but goddamn I don’t know how to get over this and i feel really lost. I want to get over this and he thinks I have. But here I am laying in bed with him while he’s sleeping wondering what I did to deserve this....I fucking look st her facebook and wonder why the fuck I wasn’t good enough. She knew I was pregnant with his baby, I miscarried and he told her right away. I just wanna know if anyone’s been cheated on and moved on in a relationship. Or Is it a lost cause.