Ok if it were me, and I had a chance to have the person I wanted, and there spouse was ok with it. Really this is a problem. I understand all the other things that you are going through and what's attached with this situation, but here's the view from a bi guy. Being in a relationship with someone I care about, if she said that it was ok to have another girl live with us and play. Man live in it, enjoy what you can with this, maybe it will work out well. Then maybe it wont. Either way you are sitting in a situation most dream of. If you look back at this many years from now and things didn't work out. At the very least you shared some love and made some happiness with all three involved. Go have fun and have no regrets