I think your HH can be any age :-) What matters is that they are interesting and the reader can relate to them!
I think the key to a good romance lies in the chemistry and conflicts between the characters, and not so much in their ages. Frequently when I read about younger characters, I find myself imagining them at my own age anyway. (And that is oooooooooold.)
I do the same thing! I guess it's part if identifying with the characters.
I wonder if we could get away without revealing the age of our characters...Would readers be able to identify with them? I don't every really think of my characters being near my age. But then it weirds me out when they are the ages of my kids.
I like the idea of spouses falling for one another again. Great answers!