My Girlfriend's Threesome Trap... So I've been dating my girlfriend for 9 months now and she has brought up 3-some's a few times. At first I said it was probably one of the best ways to guarantee that the relationship would fail (based on popular advice, not experience) and that she wouldn't really want to do it. She says she is not attracted to girls. So naturally i thought it was some sort of test. Recently she brought it up again and i decided to call her bluff and said we should go for it. She is the only woman i have had sex with and she insists this would be a good experience for me...

How guaranteed is this to be a trap?
If it is not, is it guaranteed to plunge our relationship into a downward spiral?