Are you off both the first mortgage and the title on the house? Since the house is the guarantee against the HELOC, it's possible that since you're no longer an owner of the house, you should be off the HELOC. But I wouldn't hold my breath.
My guess is that you're stuck with the HELOC, but maybe not, if you no longer have an ownership interest in the house. You could try asking the holder of the HELOC, but they want payments from anyone, so they're not motivated to get you off the hook.
I'd get with an attorney on this one. And in addition, start investigating what it would take to borrow money to pay off and CLOSE (you must close, don't just pay off) the HELOC before your ex opens the faucets on whatever credit might still be available.
* Credit is a wonderful servant, but a terrible master. * Who's the boss --you or your credit? FICO's: EQ 781 - TU 793 - EX 779 (from PSECU) - Done credit hunting; having fun with credit gardening. - EQ 590 on 5/14/2007