Guess I wasn't enough...

So I had been dating this guy for a while. Things were going great, we were happy. He went to visit back home last week and came back acting strangely. He brushed it off every time I asked him about it. Then, last night, he called me and admitted that he'd had sex with his ex while he was home. He swears it was unexpected, but the encounter made him realize that he still had feelings for her... feelings that were stronger than the ones he had for me. He ended it then and there, hung up, and I haven't heard from him. I've been fine for most of the day, but now that the shock has worn off... I can't believe it. I loved him so much, and he was able to cut me off like it was nothing. Sorry for the wordy post, but I needed to get it off my chest and none of my friends will answer the phone.