Double Standard?

so I was in a serious flirtationship with someone, we both liked each other. I am an open book, and I also have severe anxiety. When I finally verbalized my feelings, he said no because he was older and he wasn't really looking for anyone to date because of time constraints (he then mentioned really fast about how emotional I am and how he didn't think he could handle it) I accepted and we continued as friends. Well, now, not even a month after all of that, he is now flirting with the girl upstairs, who is my exact age (and my friend). he obviously made up the first 2 excuses and that kind of hurt. I am tired of people treating me like I'm made of glass, any suggestions on how to get over this whole thing?