Marriage just isn't what you think it is.
Oh I can't wait for you to presume to know what I do or do not think marriage is.
I'll tell you what I know it is, it's a social contract. In many places it's a legally binding contract. Those who violate the terms of that contract are subject to relevant consequences, including but not limited to divorce. That's not an opinion subject to debate or question.
You seem to think it's just a casual suggestion. You're also quite obviously jaded and cynical. Look, I'm not glad you got burned so badly that you think the worst of your partner and that you 'survived' with her for so long, or she for you if she agrees with you. That would make you both incredibly bad for each other. Being in a toxic relationship for a long time isn't success, it's just apathy. But hey, might as well stick with who will tolerate you, cause nobody else will, right? That's sarcasm by the way and it's nothing to brag about or be proud of.
LOL "cheating is no big deal!" is a farce. Infidelity is a deal breaker for anyone with a modicum of self-respect. If you're a serial cheater then you're a terrible human being.
Just in case you think I've never been cheated on, you'd be erroneous in that assumption as well. Fortunately I respect myself too much to willingly trust anyone who has intentionally been deceitful. There's no such thing as "accidental cheating".
Goodbye and I hope your kids, if you have any, have managed to find happiness despite your desire to grind it into the dirt for everyone around you.