In the paranormal world, it's difficult to settle on a definition for cougar--as refers to older woman/younger man. For one thing, it's very hard to define age by appearance.
Vampires can be any age. And what they appear to be has nothing to do with actual age. So that hunky nighttime pool boy could be a couple hundred years old...making the fiftyish cougar a mere babe. Or if you reverse it, that young babe in the casino could be a lot more of a cougar that she appears to be. Hmmmm.
Depending on the world rules, shifters seem to have a life span up to around three hundred years, but age so slowly it's hard to define age. Then there are all the new kids--the zombies, the demons, the angels...who can decide what's unusual anymore?
What I find interesting about the paranormal cougarish deal (male or female) is this: no one addresses the issues--the same ones you would have even if you weren't paranormal. Things like one of you has more experience because you're older. Or that because of the age differences there aren't so many common interests. So how does that work between a two-hundred-year-old vampire and a thirty-something human?
I don't recall reading even one book that deals with those issues as a conflict. And I confess I didn't address them in my own book. But now that I think about it, wouldn't there be some sort of conflict or adjustment? Or is the older protagonist just supposed to deal with their memories and move on?
How do you think that would work in "real" life?