My separation agreement states that I provide med insurance for my minor children.

My separation agreement states that I provide med insurance for my minor children. With renewal coming up I am seeing that it will be difficult for me to meet that financial requirement. The agreement was very favorable towards my ex husband who makes 3 times my salary and kept the house. He paid me less than half equity in the house and a small part of his retirement fund. My ex told me if I insisted on more he’d have to sell the house and my youngest son would be uprooted from his home - which we both were trying to avoid. In exchange he is financially responsible for everything regarding my sons with exception of med insurance. One son is in college, he’s 19, one is in 9th grade- he’s 14. 14 yr old lives in the home / I am 5 minutes away and see him everyday. Agreement states we have 50 50 custody / this arrangement is most comfortable for my son. I don’t receive alimony and I don’t pay child support although I do pay for things for my boys as they need them. If my ex were to try and require me to provide insurance what are my options? I’d like to tell him he is going to have to add them to his policy.