Sex & relationships

Okay, so I recently broke up with my boyfriend for someone else. (I don't need negative replies, yes I do feel bad & know it was wrong.) Well, I didn't actually think it was going to go anywhere with this new guy at first but that all changed very fast.. We had a great connection, and GREAT SEX. The best sex I probably ever had. But, me & him only lasted 2 weeks when he told me he didn't want to be with me, so we stopped seeing each other. There's way more to the story but I don't want to write a book. Karma! I guess everything he told me was a lie, but those were the best two weeks I had in a while! I feel so guilty & horrible saying that, cuz it's obvious he pretty much used me. & my ex was the greatest guy ever. He was sweet, thoughtful, honest.. All that stuff we need in a relationship but my dumbass just wasn't happy with him & I feel horrible about that. We still talk, but he doesn't know what I did. He thinks I broke up with him cuz I didn't like him as much as I thought I did. Idk what to do. I feel bad talking to him & not being honest with him. I know I don't deserve him after what I did to him. I just needed to tell somebody. Anybody have a similar situation before?