[capybaraStorm]

It's not an exclusive relationship. It is a highly transactional ephemeral one.

The basic reproductive qualities of females favor LTR since it takes 9 months at the very least to pop out a kid, during which time mating with other males provides no additional children for them.

It will be an interesting world if these short transactional relationships are basically available anywhere like chips out of a vending machine. I suspect most of the reason for laws against prostitution are a mixture of protectionism for prostitution rings (they need the illegality / high risk to lock in heavy profits) and disproportionately appeals towards the female reproductive strategy that is potentially at a disadvantage with guiltless "normal" sanctioned prostitution on the table at every computer and street corner.