I believe most states are "no fault states"; meaning if one of the people in a marriage sleeps around like a dog in heat - then the courts do not even take that into consideration. Hey, adultery isn't illegal; they would say - so "who are we to judge". I say - we must, in this society, root out and deal with evil; adultery SHOULD BE illegal. It us a crime and many are hurt. Among other things, it is fraud and breach of contract. And for those of us who look to God, well - it is a bunch of other things, too.
So, please be aware that as with any things - the "rights" we think we have in certain situations are delusional. If you would have told me that no one gave a crap, from a legal and asset distribution perspective, that one person screwed another person over (in more ways that one) - I would have said you didn't know what you were talking about, and I would have felt very passionately that I was right.
And I would have been wrong.
As Elmer Fudd used to say "Be caweful, vewy, vewy caweful".