I would tell the guy that I was serious when I told him to stay the hell away from my wife, and NOT to underestimate me.
But that's just me.
As for my wife, if the guy didn't back off and they still planned to meet up, I would wait for her to leave for her rendezvous, and I would call her cellphone and say:
"I hope it's worth it."
"What are you talking about?" she will say.
Reply: "I know exactly what you're doing, and I just hope it's worth it. Because once you do this, there's no going back."
She then says whatever, and you finish with "I've said all I'm going to say, but just know that there are consequences if you go thru with this, and I WILL KNOW if you do."
And then hang up, and don't return her calls or her text messages.
Infidelitus interruptus. Remember, they don't know what you know, and what you don't know, so they'll have to assume that you WILL know if they hook up or not (for all they know, you have a tail on either or both of them!).
