What should I do?

So my friend just recently found out a boy who she was seeing, is playing her with a girl that she knows. Neither girl new about each other and my friend is upset because she really like him and was going to actually give him a chance but now this happened. The boy that I am seeing is best friends with the boy who just hurt my friend. I like the vibe and connection me and the guy I’m talking to has, would I be a bad friend if I continue to talk to him? Because he was the other guys best friend so he had to know that he was playing my friend and he could’ve warned her. Would I be wrong if I kept seeing my guy even though my friend and her guy didn’t work out? Please I’m confused I feel like I should be loyal to my friend and cut this boy off but on the other hand what me and him have going on is good so I don’t wanna mess anything up