My husband is 13 years older than I am-- 59 to my 46-- and it wouldn't surprise me at all if he outlives me. He's strong as an ox and his father is close to 90. I can assure you a woman doesn't have to worry about an older husband who keeps himself fit. Of course, if he's going to sit around in the Lazy-Boy eating junk food, that's another story.
That's a character issue, though, and character is ALWAYS of the first importance.
My wife was eight years younger and died 7 years ago. I never thought I would survive her since she did everything right and me rarely. But that didn't matter.