The act itself is the motions needed to reproduce.
This is risky business, since as a male you have to fight other males for the female. This takes energy and also risks that you lose and can't reproduce. So in order to make you do it anyway hormones are released, circuits in the brain get activated, which makes it a rewarding activity. This entices a animal to go ahead with it, since logically it is a wasteful, dangerous activity.
This is how in any case mammals are wired.
The mammal Homo sapiens has created an explanation for these base emotions, something to give it meaning. They call this love. A nice cozy tale which masks the underlying hardwired drive to procreation.
If you're less given to fairy-tales of princes on white horses you see it for what it is. And then it becomes less attractive. Why bother, a beer is nice too.
There's only two things I hate in this world. People who are intolerant of other people's cultures and the Dutch.