A big part of the problem is that while men and women have differences women think their way is right and that men are defective.

Why would any man love a woman who thinks he is defective?

Women think they can change men and when a direct means such as nagging doesn't work they try indirect means such as pouting and witholding affection and this just leads to more disharmony. Men consider such indirect means as suspicious and infantile and they lead to lack of trust and respect.

Ultimately the root of the problem is that too many women want a relatinship but just don't like men as they are.