Most Helpful Guy
No he is not right to be mad. Sounds like one rule for him and another for you. It's not great to have kissed his mate but he should be angry with his mate and not you. This guy sounds like a player and possibly a bit of a narcissist. Remember he didn't turn up. He left you hanging with no explanation. He is seeing other girls. Is this really someone you want to worry yourself about?
Most Helpful Girl
If you two aren't official and him sleeping with other women isn't considered cheating neither by you nor by him, then you kissing another guy isn't cheating either. Have you asked him to clarify how him sleeping with other women and you kissing another guy are not the same thing? I'd love to hear what he has to say about that.