Hang on. YOU ask THEM if they are into mm play, and when they say yes, you write them off?
There is a strong possibility they HAVE read and understood your profile and are willing to comply with your rules. Just like full swap people will rein themselves in when they are with a declared soft swap couple.
Do you think they are wolves in sheep's clothing and as soon as they get they chance they are going to suck your husband's cock?
Perhaps I misunderstood your post but I think you're out of order here.