2) It's ok to gently plant some seeds of doubt. You can (calmly) tell him he's always going to regret leaving you, a loyal loving woman, and he won't be happy when he sees you with a new man. You can also tell him that iF HWW would cheat WITH him, she'll also cheat ON him, and he'd better watch his back (he of course, will say she would never do that - but t6rust me, it'll stick in the back of his head, especially with the age difference!).
3) You can also tell him that it's one thing to ditch you again, but he CANNOT ditch his kids again and he is causing them irreparable harm if he doesn't start putting a hell of a lot more energy into his relationships with them. Tell him you expect him to man up and be the father they deserve.
Then - go on with your life. Seriously. Get out and socialize. Go on a few dates (but keep it hidden from your kids, they don't need to know this yet). Take the kids away for a fun weekend trip.
Oh - and get some tax advice before you start talking to him more about the taxes. I'm not sure what you're talking about, but if he sold a property you jointly owned as an investment and claimed the homeowner's tax exemption for a home he lived in, he does NOT meet IRS rules (you have to have lived in that home for 3 out of the last 5 years in order to take the homeowners exemption). Not sure how that would negatively impact you, but see a tax specialist before you talk to H more about it. Get your facts first.
