He did me Dirty

So I had a guy best friend, and one day he came out to me that he had feelings for me and and all this stuff, I was scared to fall for him because I knew he was a player and he knew I was a player too, but we went along with our relationship, and became a little bit more than best friends. We basically were together, and was going to ask me out a “special way” this coming up week, but yesterday he went to a party, and kissed and flirted with another girl he supposedly had “loved” before. I was hurt when I found out, and now I lost my best friend, and the guy I liked, but i’m the one being blamed, am I really guilty though?