In a no-fault divorce, neither side needs to prove that the other party was guilty of something that caused the marriage to break down. No blame is assigned.
All states have some form of no-fault divorce.
Some spouses want to prove that their spouse is to blame for the break down of the marriage. The grounds for this type of divorce may include adultery, physical or mental cruelty, insanity, habitual drunkenness, and desertion. Whether or not fault is considered when dividing property or deciding support and custody varies from state to state.