He fobbed me off for another girl?

I was seeing a guy, who is really hot and definately a charmer. I was happy but had my doubts because he was very touchy feely. I found out I had to go on a family holiday for a week to Tenerife, so I went. I signed onto MSN during the holiday and he came on and instead of the usual "hi baby, my love" etc.. he just goes "hello" and then shock horror......"listen, i met a girl last night, and i think i like her, i hope you understand, you know her, shes in a group photo with u on facebook".....i am so angry. she is in a group photo.. i dont even know her but she is popular and not even that pretty. I have a better figure. Not trying to big myself up or nothing but i must stick up for myself. He still talks to me online and its coming to the endo fmy holiday and i know when i get back, they will be all over eachother infront of me. He dropped me instantly and i dont know how to react. I want to make him feel AWFUL about what he did, guilty and everything. HELP! Whats your view??