Why does it seem like men are forced to fight for sex?

Why are men expected to spend money and/or do activities to try to get sex. It just doesn't seem fair. I know that the odds are that it won't even work. I mean the vast majority of women don't even have sex. If sex is a natural human instinct then why is it not available to both sexes? I guess the only reason I see is because of the fact that we have an oppressive government that prevents men and women from competing fairly and on an equal ground. <br><br>&#x200B;