If this was the case, then no I would never accept. Firstly, not only because I think that this is immoral but because I believe that women are not objects that are to be traded. Often at times, people tend to classify women as sexual objects.
My girlfriend would obviously have her own life and her own life choices, and she would not be bound to the choices that I would make for her. Secondly, even if I had the right to do this, I would not accept it on moral grounds and would consider it to be nothing but cheating.