Never fcuk with someone else's man. I have been on both sides of the fence and I have never seen it work out pretty for ANYONE involved.

If you can chill till he has sorted it with his woman - more power to you.

No one can help who they are ATTRACTED to. But everyone has control of their actions (whether it is sleeping with someone or consuming too much alcohol). It's your CHOICE. So I hope that you can give his partner enough respect that they can end it gracefully. I strongly believe that what goes around comes around. Doing the right thing now might mean that you guys can make a go of it together in the future.

good luck.