What a terrible sitch for you....at least as far as the kids are concerned. It certainly doesn't sound like there has been a lack of trying on your part. I've had some visitation difficulties with my ex, but never on the level you have faced. You've been a saint to keep plugging away through it all.
I don't want to be anti-DB, but unless by some miracle your X starts treating you with respect I don't know how you could even consider having him in your life. I know that seems bad, but you (like a lot of people on here) deserve better. Maybe over time when you've done the things with your life that you want to accomplish he'll see the light. But maybe you will have moved on by then.
Best of luck Jo. I admire the strength you've shown in not so easily giving in to his feeble attempts to apologize.
In the end, it's not the years in your life that count. It's the life in your years. Abraham Lincoln
It is hard to fail, but it is worse never to have tried to succeed. Theodore Roosevelt
