Divorced from wife 15+yrs and still covering her health ins. Kids have their own coverage and she expects to be covered forever.

Divorce decree addendum stated that she would pay me the difference if there was an additional cost to cover her. To date she has never paid me and being on the family plan, that is significant $$$. The kids have their own coverage (27 & 25 yrs old) and with my open enrollment coming in Nov. I have to make a choice to discontinue her coverage as of 12/31/09 and let her take me to court, or for me to get counsel and show that she has not fulfilled the terms of the agreement and any further coverage should be terminated year-end. If I am forced to continue coverage, some mechanism should be put in place to insure payment from her so she does not get a free ride like she has the last 15+ yrs. She is self-employed and has not re-married and no plans to do so. ..Please help!!..Thanks