I agree with Saffie, too much pressure will push him away. Don't give out empty threats. If you do that he'll never take you seriously. And if you give an ultimatum make sure you are entirely prepared to follow through with it.

In other words, are you ready to divorce him today if he continues the A? If so then give the ultimatum (and line up a lawyer, get the financials figured out, custody, etc...), otherwise, you have to learn to live with the situation and make a great life for yourself and the kids in spite of what he's doing.

There is no arriving, ever. It is all a continual becoming.