What does it mean if my ex wants to keep me on his health insurance plan?

My ex-fiance and I have children together and were on a family health insurance plan through his job. After he broke up with me, he kept me on it. We've been broken up for almost 2 years now. He lost his job a couple months ago so now we no longer share a health insurance plan. I recently told him that I'm going to start buying my own health insurance but he told me to wait and that once he finds a new job, he will add me on to his new health insurance plan. Why would he do this if we are broken up?
What does it mean if my ex wants to keep me on his health insurance plan?
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