What is the most Years for a Dating couple?

This question is for some of my single friends....Let's say you are deciding to date and you are at an age that you are looking for a marriage mate and you are a woman. How much older should the man be and why?

Thanks everyone...
Update: Added thoughts: When I was younger I dated a couple guys that were from 8 to 10 years older. At the time it seemed exciting even. It is accepted but if a woman dates a guy 8 to 10 years her junior people would criticize both of them. Society is interesting in their beliefs...but hoping for some good answer here.
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