@Anotherlongdrive you are not understanding what drives affairs.
"I think if people felt more free to leave a relationship and move on, I dont think there would be so much heart break. " is not the issue!
The truth is, the people having the affairs want the OP AND the marriage. What's not to like. All the domestic stuff like kids and laundry get done, AND you have the secret thrill.
Otherwise, it wouldn't be secret, would it! But we know that they want their cake and eat it, BECAUSE they 'pretend monogamy' to the unsuspecting spouse, who is continuing to do their duty (from money to gutter maintenance) in the mistaken belief they are in an exclusive relationship.
My ex never wanted to get divorced! Even when we were divorcing he would write to me asking for it to be stopped! Did that mean he loved me? No, but I was useful, and it meant no financial consequences. Clear cut for him, my trauma and heartbreak that I meant so little and my precious family was destroyed for what?, took pretty much a decade to fully come to peace with.
THAT is what is so violating about affairs. It is intimate betrayal by the person you let into your heart, and it is fraud (deceit in order to gain an advantage).
Funny, in business and matters of national interest, betrayal and fraud are criminal matters, but families are just supposed to suck it up.
No only must they suck it up, they are now being pressured by society to be Happy that cheater parent is now Happy. And children are Happy and must Happily accept the instant parent replacement because their cheater parent is Happy! So lets all do the Happy Dance.