The main problem: I recently told my boyfriend that I had slept with my ex-boyfriend a couple of times when he had broken up with me about 6 months ago. He asked me back then if I did anything while we were broken up and I lied, told him I never did anything with anyone. Now, down the road, we are in love, we ultimately want a future together, a house, kids, the whole nine. But now that he found out I had been keeping that lie from him this whole time, he feels as if our whole relationship has been a lie and cannot trust me and wants to know why I did it, why I lied about it, and why I kept it from him for THIS long, and how I could possibly live with myself knowing that secrect and how much it would kill him... How could I respect him and how have I been truthful since, if I've held onto that big, bad, terrible lie.
Now, a little bit of the backstory and details:
I've been dating my boyfriend on and off for a little over a year now. Things were really rocky in the beginning, and he was even seeing and sleeping with another girl (who happened to be his upstairs neighbor at the time) for a couple months last spring, and doing so 100% behind my back. He also lied when he told me he ended things with her and only came clean when me and her talked to each other and confronted him together. Around that time we would break up on occasion, usually he would be the one to break up with me, for usually the same reasons: I didn't open up enough, I didn't have enough direction/ambition, he just didn't know what I was thinking or what I wanted to do with my life. Around that time, on a couple of different occasions that he broke up with me, I spent some time with my ex-boyfriend, whom I'd stayed very close friends with, and we ended up having sex. I've since stopped talking to my ex-boyfriend out of respect for my current boyfriend (even though me and the ex wished to remain friends), and have not done anything since, nor lied about anything since.
And this whole relationship I've caught him in several lies and situations of him contacting other girls, mostly ex-girlfriends that he loved, telling them he wanted to be w/them, flirting, saying sexual things, ect. He claims he did that b/c he wasn't happy with us, b/c he wanted validation when I wasn't being attentive enough, b/c he thought I was probably doing the same... and he also claims I've caught him in every single thing he's done wrong and figured out every lie. Additionally on a couple of occasions when we broke up he was sexual with other girls. But he told me about it. After some proding. I'm still unsure if he's told me.. or admitted to, rather.. everything. And that can partially be based on a couple of random small things I know or knew that I didn't confront him with, and he didn't bring up, but yet he insisted that I had found out everything.
I want to move past this .. We BOTH want to move past this. How can we both do so and trust each other again. And how do I get him to trust me again?
I do know that lying is wrong, no matter the justification, and I will never lie again. I did so selfishly because I was scared of his reaction, and wasn't really sure that he was completely honest either.