Same thing with 50 year old men with 20 year old wives. I am in my early 40s and there is no way I will marry woman in her early 20s, unless she is very special. Sure, 20 year old bodies are attractive, but maturity difference is too great. The movies are fantasies, showing off women at the age of peak physical attractiveness, with just enough immaturity to make the man feel more responsible by contrast, but without any of the quirks of actual immaturity.

Having a 20 year old sex partner is another story. And many women are willing to let you live your fantasy, for a time, for a price...