My suggestion to you would to be to have a night in with the other couple. Dinner, chat, see what happens. If you and your friend end up "together" then great, if not that's ok too. Make it a night with no expectations, a night with friends that could lead to more. But only go as far as you are comfortable with. No harm done if you don't have sex with her. If it's right it will happen and they always say good things come to those who wait. Good luck. ~smiles~