In my opinion, there are at least two causes for a woman to legitimately abandon her husband: failure to provide and severe physical abuse. I derive that from rules in Torah about what a man owes his wife and how he is to treat his servants. If a slave may go free if his master breaks a single tooth, how much more must a free woman be allowed to leave? The only explicit rules for divorce in Scripture are about a man divorcing his wife, so I'm less sure about whether or not she can completely divorce him.

I am aware of both Jesus' and Paul's teachings on divorce and marriage, and I do not believe I am contradicting either one.