If you're talking evolution, that argument also applies to women as well. We, as a species, are still alive only because our instinct to pass down our genes. Same with every other form of life.
There's a lot of evolutionary processes that don't have to do with having more offspring, but increasing the viability of less offspring. Having kids, no matter the species, is a very costly affair. You could argue that mate selection generally reduces the number of offspring, but increases the viability.
I've read a hypothesis (very much unproven) that having some gay members of a species increases the viability by having more people to care for the offspring without being in mate competition. It's called the gay uncle hypothesis
People who can have sex but choose when to reproduce experience more satisfaction and control over their lives, which leads to better outcomes for the children they interact with, who will most typically share a large number of genes, since the children we tend to interact with most are family. Children who experience better outcomes are more likely to themselves raise more children.
All good things for your common man are evolutionarily beneficial.
It should be noted that evolution doesn't care about individuals, so not only behavior which increases an individuals chances of having children are incentivized. Evolution happens in a population, which is why it is advantageous for a group to have selfless traits.