If I were in that situation, I can honestly say that I would be raging pissed
I would never see that couple(or one half of it) again. I would tell her why she is no longer welcome in our home & kick her ass to the curb. That was terribly disrespectful on both her part, as well as your husband. I would sit his horny little ass down & explain exactly how he stepped out of line just in case he played stupid.
If he's sorry and agrees to let this couple RIP, I would be willing to try again with A DIFFERENT couple-as long as the rules are clear.
The fact that this bothered you makes it valid. Talk to him & find out what in God's name he was thinking that made it ok in his mind. If he still doesn't get it-perhaps y'all should take a break.