Let's talk relationships

So I was talking to this individual one time and they were saying they wouldn't leave their significant other because of infidelity. They were saying they'd fight as long as the significant other still wants in.

Personally I think she's right somehow. Imagine getting a divorce after years of marriage just because your significant other opened the door of infidelity and let someone shake your marriage. If he still wants to be with me then I'll have to find a way to deal with it not give up on my marriage. I'm the type that would also bring another person if the lonliness is getting too much. Don't judge, I'm only human 😅.

What's your take on this?