Whats his game ? Should I walk away before I get hurt ?x?

I had that same thing with this friend of mine, but i knew he was in a relationship but we fooled around anyways. Once him and his girlfriend broke up for good, he didn't talk to me again till he was in another relationship. I can say from my experience he's not worth it girl, walk away before you get hurt, cause he's just looking for some side action.