Does this make me look bad?

My ex and I have been broken up for about a year. He has had a new girlfriend basically the whole time. For the past 3 months he has been telling me he wanted me back and he would leave her for me. I fell for it of course (I know, stupid). Then about 2 weeks ago he told me we were done and he was sticking with the new girl and we can't talk anymore. On the weekend I kissed his friend for maybe a few seconds (not to get back at him, just happened then we were both like wtf). My ex found out and he is super mad at me? Does this make me look like a loser/slut?