Yes! I have a few (too few) clips where the plot is a couple submitting to one mistress. Alternative marriage counseling is one I've seen a few times. Another plot I've seen a few times is that he secretly has a mistress his wife finds out about, the wife decides to confront the mistress, mistress makes both submit. A little more confrontational than alternative marriage counseling, but a little hotter because of it.

I have always fantasized about doing a scene with two women where there's one domme who is dominant over both of us, but both women are dominant over me