When will he divorce her? If the question has to be asked, then the answer is probably, "Never." The question implies that it has already been too long and that the promises are not being kept.

Why would a woman hang on, when it would appear to most outsiders that there is little chance of him leaving his wife and marrying his mistress?

The answer is never simple. Every person has their own story. However, it is usually some kind of emptiness story. It may be a woman in an empty marriage, waiting for the fulfillment promised with her lover. It may be a single woman unsure of her worth and glad to receive what attention she can. It may even be a very accomplished woman that has "fallen" for a man that "sweeps her off her feet" and then won't come through with the finish of the story.

In each case, there is the initial titillation of playing the hide-and-seek game. While this game grows old for the woman, it continues to provide adrenaline and thrill to the man. This is a reinforcement for continuing with things as they are. He may feel like the guilty school boy, but there is a large part of him that enjoys it.

It's not that he doesn't care for her. He undoubtably does. But he also cares for his wife, his children, his home, his car, his career, and hisgood standing in the community. He cares, but not for her alone. It is obvious from his behavior.

You might wonder how a couple could allow themselves to get into such an untidy if not immoral position to begin with. It's been my experience that, except for the serial cheaters, most couples slide into these relationships through companionship, not expecting anything more to come of it. Some get there because their values allow a casual fling and they find themselves much more deeply attached than they ever intended.

So, what do you do, if you're asking about when he will divorce her?

You could expose your relationship with him, hoping this will force his hand and he will leave her. Alas, he probably won't. You'll probably just force them into marriage counseling together.

Your best option is to find a life for yourself apart from him. Very few people can leave a relationship without another to go to. So, force yourself to date others. Attempt to find relationships that promise as much or more than the one you are waiting upon.

If you are married, then get to work on that relationship. See a marriage counselor. Work out your issues in the context of your existing relationship before trying to move on to another.

Oh, and what if he does divorce her? He cheated once (with you), why would you ever trust that he wouldn't cheat again, this time on you?