It would be awesome if your wife walked in to challenge her. Giving your wife a beating and screwing you when she plants her to the mat.
I was thinking along this line of action, exactly. Or, you could first comply to your (as yet) nameless wife and Molly, and spar a couple of rounds with Molly's husband, the women doing their best with their «vicious tongues» - your words! - to keep their husbands rock hard between rounds. (That story could be posted in the m2m section, if it would not fit here.) The best would be the next week's wife's boxing, with your wife losing badly, with the result suggested by SNW. And if your readers are lucky, a revenge match demanded by your wife in which she throws away the gloves and takes the older rival all-in, catfighting and using their «vicious tongues» again, this time on each other...
It would be a pity if you didn't pursue your efforts in writing.