Ellie's idea about dressing up is a great one. I didn't let H know my plans yesterday and although he didn't say anything, I think it got him thinking.
As for the legal stuff...I know you have talked to a lawyer already. Sounds like it is time to retain one. From a legal standpoint, I would think that your H didn't only abandon you but also the kids. He can call it what he wants, but the law may see it differently. I think he gave up some power when he choose to move out.
I also agree w/ Ellie that you should create conflict. On the other hand, I'm very proud of you for standing up for yourself. I didn't notice you mention any tears. Great progress Supermom! Once again you rock!