In an equal relationship, I agree. I suspect a lot of women think just showing up naked is enough. But there are some factors at play.

One is that men are pretty easy to please, while women are more complicated. It's not a question of fairness - it is inherently more work for us because biology and sociology.

Another is supply and demand - women can have sex pretty much anytime they want. To stand out in a crowded field, you have to bring something extra to the table.