CeMar, staying together for the sake of the kids is like laying a minefield. My late H stayed in his marriage for the sake of the kids, and his 20-something daughter never forgave him. (She's 30-something now.) She wouldn't go in the hospital room during his last hospitalization, and she had to be dragged to his funeral. This is a common reaction. Look for a book called "A Grief Out of Season." When you pull the plug on the marriage after the kids are grown they feel that you have invalidated their entire childhood, that it was all a lie. When you D when they are still children, there is a chance to still have some good memories of childhood. Also when you D when they are children, you are THERE to help them through the D. After they are adults, you don't see them as much. They feel that you have kicked them out of the nest, and then burned the nest. I'm not making this up. There was an article on this recently on the net, but I don't have time to look for it right now.
If you don't leave now, you better plan on staying forever, because if you wait until they're grown, they'll never forgive you for deceiving them.