In theory, the man should be older than the women. I say about 10 years such that when he's older, she is still youthful and pretty or in this case, the hotter one.
This prevents him from cheating cuz if he got a hot thing at home, why cheat?
Now if he's the hotter one, don't blame on him if he looks at other women who are way hotter than you.
Stupid theory is just that. Theory unclassified.