Depends on the definition of prime and factors like which perspective are we seeing it from.
When we say a woman is "past her prime" it's usually referring to beauty, reproductive capability, youth, pleasantness to be around, and is from a male perspective.
Assuming we are seeking to define a man's prime from a female perspective, given the nature of women, why even bother defining it since it'll change in a few minutes depending on how she feels? Does such a thing even exist?
Sorry for the long winded response. I guess ultimately I'm commenting on how a "man's prime" and a "woman's prime" aren't just mirror images of one another as a gynocentric society would have us believe.