My ex-wife use to have a 'boy toy' who actually ended up moving in with us for a short period of time when he lost his home to fire. For me it was actually pretty hot to come home and find them going at it. I love sloppy seconds anyway, one of my kinks!
After who 'boy toy' moved out, after an entire summer, the house 'felt empty' so she asked one of her girlfriends move in and got a 'girl toy' and that is what killed our marriage. While I throughly got off sharing her she couldn't, and didn't, handle sharing me.
So the moral, find a common ground and a stick to it. Like they say in diving: Plan the dive and dive the plan!!! Works here to!!!