Are there stories in which a couple is more or less happily Married and then out of the blue the Wife's Ex comes back into the picture? This in turn causes turmoil in the Marriage as the wife is assaulted by a barrage of old feelings she hasn't quite reconciled for her Ex. The Husband of course senses the threat this other guy poses and moves to take action to neutralize that threat to save his Marriage (doesn't 'have' to be violence but kudos to being proactive). Could be a wifes Ex-Husband or ex-boyfriend. It would be preferable if the Husband stopped any sort of affair before it turns sexual but not exactly a prerequisite. So long as it's not contrived RAAC BS.