I've seen lots and lots of couples and very rarely get guys 'pretending' to be one, I can usually spot the bullshitting ones straight away.
I don't always ask to speak to the other partner either (sometimes the woman rings me to arrange) I assume that whoever makes the booking is responsible for the behaviour of the other party. Most of the couples I do see are professionals, very clean, polite and good fun to be with, several have been booking me for years and we have become almost 'friends'. I really look forward to meeting with those types, and enjoy the variety.
But I have also had a few bad experiences where I've gone to a couples house late at night after they have been drinking, I learnt that's a recipe for disaster and I don't like 'gate crashing' on someone's party so I refuse these ones now. The only way I agree to couples bookings is when its established that I'm ultimately in control, its a 3 way thing, I'm happy to 'party' with them but won't be just a 'plaything' for their drunken entertainment and also you get some couples who like to use other people for an 'audience' for their domestic issues/disputes, I refuse to be any part of that.