Hello,
If you are reading this and this manga is over, these words are meant to you.
Here is my prediction: His power is over wives as shown by the first chapter, thus it can work on any "wife".
He did not see who his wife was sleeping with.
My prediction is that somehow, his wife was sleeping with his future self who came back from that Isekai world with that same power.
I won't be able to find out, since I AM NOT READING THIS THING, Whoever would read it would have some odd preferences...