I think the general message is that it'll cost both of you more if it gets
dragged out. However you can reduce your costs by self-repping - if he's
paying a lawyer while you're doing this, he'll be the one with the biggest
bill!
If I were you though, I think I'd probably take the money
and run. It's not just about the cost of court action to get more, it's
really all about the emotional aspect of it. You'll end up wearing
yourself down into a wreck if you do have to fight him, and you have to ask
yourself if it's really worth all that.
50%'s pretty good if
he's agreeing to it, more than some of us will end up with...
Best of luck with it all.

WCX