listen i dont think that three somes in a serious realtionships are good at all and i speak from experience, there could be alot of emotions flying high here in the end and you can open a can of worms...and so on starnger or not i dont suggest this. I set up ground rules and those rules quickly went out the window and then there was a big fight. you need to realize this can go one way or the other. Is it worth the risk?