try to get background info about her. if the info is good, find out if he likes you and carry on.if its bad, its wrong but tell the boyfriend and have witnesses.
If you like a guy and he has a girlfriend then you should back off and only try and be his friend.
If the boy has a girlfriend, find a guy that doesn't have a girlfriend.
wait
...
He has a girlfriend. So you butt out. It's not complicated.
you use his girlfriend like a ladder and jump over him
Well, its ok for them to hang out. If you trust her, then yes, if not then go with her. Like a double date.
Spy on him! A wife caught a guy redhanded giving nude photos of himself to his girlfriend.
You shouldn't flirt with him if he has a girlfriend.
littlekid
Yes.
you can tell him, or his girlfriend if you are friends with her