No, I don't blame you, I wouldn't want to be put in that position either. Gosh, such a sticky situation. When, my SIL told me she let another man kiss her (when her husband was in another room) I didn't say anything - to her or her husband. I told DH just to have it off all of my shoulders but neither of us said anything. I think maybe this was just one time thing with them (out of intoxication) and probably won't happen again. Maybe you can say, 'If I see this happening again, I will tell your wife.' Or something along those lines....