ITT: a lot of “either/or”
I’m not sure that evolution cares one wit about any of our theories. If it means I’m the dad and I’m the dad more often… then it will be favored.
If I enjoy it more, she enjoys it more or it means that my sperm have increased likelihood of winning… that’s all that matters.
And when I say “or” above, it can include any of those things. It need not be exclusive.
I’m extremely down in Facemeta. But no one is entitled to the services of another person/entity (without a contract/agreement).
You can require payment, that’s fine. But you can’t require they use or carry your service.