This can often create a conflict. 

That is a well-staged photo because yes, the woman is NOT happy (her body-language is screaming this), while the male is fine. 

In relation to sex (I will read the article but haven't as of this writing) the old truism is I think largely correct - when it comes to sex, males need an opportunity, women need a reason. The joy many women derive from making love is the increased "closeness" that results, not so much the physical pleasure of either person. Obviously many males often feel very differently - for them (us) the emotional closeness is just a nice extra.