WTF THE WIFE IS SO FUCKING STUPID HER HUSBAND CHEAT ON HER AND SHE STILL LOVES HIM !!!GOS...

She doesn’t know he cheated. She should not be blamed for her husband being unfaithful.

But he already cheated once before and apparently she forgave him then.

http://www.mangago.zone/read-manga/anata_ga_shitekurenaku_temo/hs/mpn_chapter-2412620/pg-10/

Nope you had misunderstood, if I remember correctly, he means that before she confronted him about not wanting to have sex with her but she endured it and didn't leave.
http://www.mangago.zone/read-manga/anata_ga_shitekurenaku_temo/hs/mpn_chapter-2117171/pg-20/
This time if she finds out he cheated on her, she'll definitely leave him...