He also kept his feelings about her from me for as long as 2 months (he said it was because he wanted to make sure they were real), and when he did decide to say something, it was to her first and not to me.

This is the big red flag to me. To me, this looks like he wanted to secure a second chance with her before breaking things off with you. He probably realized he had a shot, waited until he was sure she still had feelings for him & saw how she would react when he confessed his feelings to her. She must have reciprocated, leading him to ditch you for her.

If she didn't reciprocate those feelings, I doubt he would have dumped you. If it was really about feeling guilty about his feelings, he would have dumped you when he FIRST started having those feelings, not two months later. It doesn't take two months to decide if you have feelings for an ex, seriously.

I'm SO sorry he did this to you, regardless of why or the specific details. Chances are if you stay in contact, he may try to get back with you, but only if she leaves him. You deserve better than someones second choice.

Also, love isn't JUST a feeling, its also how you treat someone. Its a verb, to love someone. If you love someone, you don't keep them on a hook while you try to figure out if you can get with another girl.

I think that its awful that he's handling it this way, hitting you with a breakup out of the blue. But if he wanted to be with you, i think it would have been a discussion, not a break up. Lots of people have feelings for exs. But if you say "Hey honey, I really love you but my ex got in contact with me and some feelings are starting to come back." Then you could have talked through things and decided if you wanted to try to move passed it or break up. But he made the choice on his own that he would rather try to be with her than try to work through it with you. You said so yourself that he even admitted it to her first.

I'm sorry :(