Perhaps, now that both of you are realizing that you are both turned on by her being fucked by someone else while you listen, she will be willing to branch out to other men. The more men she has sex with, the less likely it is that she will begin to form emotional ties.
Seems like we might be having a round 2 this Saturday. Her friend has been back up here all week but she has been a little unwell and he has been busy. However he might be round on Saturday to make a day of it (or her I suppose ) and then leave just before I get home.
If it happens work is going to be very hard that day I think, especially if she keeps texting me...