When were US women no longer the property of their husbands?

Wives were never their husbands property. The wife's property did become her husband's. But a husband could not sell his wife. Divorce was hard to get so he couldn't even leave her. He was obligated to support her. He had to protect her. He could not kill her. If got a divorce and it was considered his fault (e.g. he committed adultery) he had to support her for the rest of her life.

In Western cultures since the middle ages a dowry, paid by the bride's family to the groom, was more common.