Why is Divorce always the 1st option?

I see alot of women who comment that they will leave their husbands or boyfriends if he cheats on them...my question is this; Why is divorce or separation the first thing that comes to mind when this issue of cheating occur or the first thing we suggest to someone if it happens to them?

I understand leaving if it becomes a repetitive thing...and I also understand the "doormat" philosophy however, if you leave everytime you get cheated on, when do you decided to stay and stick it out?

No relationship is perfect right?

Let's say he was everything you every wanted in a man...would you still leave him if he cheated?

Leaving does not always mean you will find better.

You'll always have a vice you run up against in a relationship i.e. finances, addiction, verbal abuse, physical abuse, children, in-laws etc

Help me understand...

Why is cheating always the end all?

Please note: I'm just sparking conversation