What should I do? Ladies advice greatly appreciated.?

Take it from someone who knows...the best thing you can do is tell her you wont go out on "dates" with her anymore until she is rid of the boyfriend. She's cheating on him with you, dude...that's not cool. It doesn't matter if nothing went on, if her boyfriend doesn't approve, it's wrong. Do you want to be the loser who this girl cheats on her boyfriend with? I'm betting you have more self-worth than that! What you need to do is tell HER to grow a pair and make a decision...she's not being fair to either of you.