A 5 year age difference is one thing but if you think more than that is ok - think again. Most women don't want to be at home with a sickly elderly husband while they are still young and strong. Nor do many want to spend a good length of their golden years alone because their much older husband passed on.
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.