Would you tell his gf?

A guy with a car page followed me on ig and started talking with normal conversation but it's almost as if there was flirty undertones in his messages. Anyway I got a superlike through on tinder from him. I said to him don't you have a gf? Cause I saw him tagged on her photos. He said yeah there's no good way of explaining this is there. I've got screenshots of everything and blocked him now. But should I just send them through to her? Or should I mind my own business since she could know about it