Giyuu has been cheating on you since the start of your arranged marriage, he knows you know, and he doesn't care, simply because you didn't.

Perhaps if you had mentioned it to him he'd stop, and one day you did, after it was brought up to you, you didn't care much about it except it was ruining your reputation.

Bringing it up caused an argument between the two of you, curses and insults thrown and echoing through the room. Giyuu sighing and trying to "explain."