The trouble isn't just the cheating per se, but the lying; deviousness; did; ego trip; thrill of the chase/ conquest; enjoyment and thrill of going behind your back; gambling on not being caught, disregard for your feelings; lack of compassion and empathy; lack of foresight; preferring the company/ sex of another; lack of morals; lack of care; enjoying the humiliation of you; not valuing you; lack of trust....the list goes on...those are all the other character flaws you have to contend with when your partner cheats.
You'd have to have a serious lack of self worth to want that in your and your DC's life.
Or you could turn a blind eye to it all like a friend of mine did after putting up with a serial cheater after 22 years of marriage.
Do you know what made her finally give him the boot apart from becoming a shadow of her strong, intelligent, independent and feisty self?
Her RL friends told her to think about what sort of role model she was being to her teenage DDS. Why was she being a doormat and loving him when all he did was take take take take and cause her untold humiliation and misery.
She realised she couldn't pretend to play happy families to everyone and her DDS any longer. His humiliation of her was complete.
But she didn't want her DDS to follow the same pattern: put up and shut up.
Now she is in a wonderful relationship with a great man and she wished she stopped trying to perpetuate a myth for all those years that all was well as it just made people feel sorry for her, no one believed her fantasy and she damaged her mental health in trying.