Just like infidelity and divorce is good when the marriage was doomed due to personality conflicts.
It frees 2 miserable people, to find 2 other people, to potentially create the optimal condition of 4 content people.
The behaviors of the contract signers in the real world seems to be far more important than any recorded words on paper.
The US government and its leadership break promises repeatedly. Endless memes about things politicians say and do. Its citizens aren't defecting en mass because of it.
None of this is that surprising.
We've seen the plays before.
"The Thirty-Six Dramatic Situations"
https://en.wikipedia.org/wiki/The_Thirty-Six_Dramatic_Situat...
You're making a lot of assumptions about a relationship you weren't a part of, here.
They were together since early college, she sacrificed her career to support him (his words). Nobody's obligated to stay in a relationship if they're unhappy but cheating with multiple people is wrong.