How do you think it would play if you went to the mediator or collaborative L with your H? I know you've let him know this isn't what you want, but would it hurt to listen to what they had to say? I might say (to H) before hand that I would listen, but that it still isn't what I want and I won't help. It might depend on how much you've said this to him though. I would make a point of saying I'd be willing to listen, just b/c I wouldn't want him thinking my going was a message that I was "on board" with it.
If you do go, I'd listen carefully and then (depending on sitch) possibly put out there that you consider this a "breach of contract" (as you thought you'd be married for life) and as such he'll have to buy out your contract. If you don't have any idea what you'd be asking for, it might be a good time to consider this. I'm sure others will have valuable insights, but like any negotiation, have your bottom line in place (that doesn't mean you start there....).
I don't think it would be a bad idea to get as much info as you can first. Do any of the L's in your area give free consults? Just a thought...
