I feel for you, thats a crappy situation, I do understand the curiosity :) I would say that if you had no other reason to believe anything sketchy was going on before this, I would not be that concerned. Women have an amazing intuition that seems to allow them to be some how clued in to their man's behavior. As far as the threesome idea is concerned...I would say that he probablly IS very interrested in a threesome (as most men are) and just likes to fantasize like others have mentioned.