We have met a few guys who have told us up front they are married, and we always try to take a firmer stance towards them, in as much, that we attempt to befriend them deeper, to get to know them better before committing to anything more, if we're both not happy with him, it just stays as friends, but if we knowingly knew he was cheating, behind her back, without her consent we would be far more reserved and we'd not even possibly have even met, and if they are lying, then if we spotted it, we would leave, but if not, if it developed, then so be it, with threesums especially I think this doubt is always going to be there xx