https://www.dlsite.com/comic/work/=/product_id/BJ268602.html
As always, please support the artist and buy his works.

Falling Back in Love With My Stolen Wife

A wife who dresses and smiles for her adulterous partner. Why do I fall so madly in love with the sight of such a wife, even though I should have been betrayed...?
--Yugo, a company employee who has been married for three years, thought that "my wife and I don't have sex, but we have just settled down in our marriage.
One night, however, he realizes that he can't get aroused when he comes on to his wife.
Later that day, he comes across his wife entering a hotel room with a stranger...
――Normally, this is a situation where you would immediately jump out and criticize.
However, at that time, Yugo's heart was not filled with anger or sadness, but with the same passion and excitement that he had felt when he was in love with his wife.

English Webtoon version (complete): https://comiko.net/series/80620/kekkon-3-nenme-netorareta-tsuma-ni-koi-wo-shita

The final chapter single handedly ruined an above average series with that ending.

Base +18, Fofotron +10