Why the hell do men get married then?
First, a disclaimer: I am not married, and I don't have kids.
But I had girlfriends for very long periods of time. I really did not enjoy spending alone time with them, for extended periods of time. Like a vacation for example.
I also have many nephews and nieces, that are below 8 years of age. I also have limited patience and energy for hanging out with them.
In general, women and children have more in common with each other, than with men. That's why for most kids, their first love is their mom. They only notice their dad later, and then at some point the dad eclipses the mom. Such is the way of nature.
Regarding why men don't like "hanging out" with women, is because that's what they do anyway, the rest of the time. I see her in the morning, at night, on the weekends, and so when I meet my friends the last thing I want to do is spend more time with her. Meeting friends is a chance to decompress.
I feel it's somewhat unnecessary to explain why men don't like hanging out with kids for more than a few hours at a time.