Retirement dilemma: Paying for a younger spouse's health insurance until Medicare kicks in

Dear Liz: My husband and I have started discussing when he’ll retire. I’d like him to retire somewhere around 65 or 67. He thinks he’ll have to work until at least 70, if not longer, for health insurance coverage for me. (It’s possible that he could do so, since his is an intellectual job where experience is highly valued. Several of his colleagues are in their 70s now, and one retired last year in his 80s.) My husband is 51, and I will be 41 this year.