Try thinking about it like music, OP. Some people are just not very interested in music: they don't actively object if someone else has the radio on, but they do not buy music, actively seek it out, or have much of an idea what to say when someone asks them about their favourite songs or musicians. Some people are keen on music, have particular bands they will go out of their way to see live, buy lots of records and also like to read about music. And some people like to make music; they sing, or play instruments and would be very unhappy if they were told they had to stop doing that now, because they are 'too old', or because a partner objects to that interest.
You could make a similar analogy with sport.
Humans (and some mammals) evolved, broadly, to find sexual activity pleasurable rather than just necessary for reproduction. Some human beings are much more interested in recreational sex than others are (don't forget that plenty of sexual activity doesn't involve PIV anyway).
It's fine to have a low libido just as it's fine to have a high one. There is nothing wrong with fetishizing monogamy/commitment when it comes to your own sex life (and monogamy and romantic love fit the definition of sexual fetishes pretty well - the fetish object needs to feature before the fetishist can enjoy sex...) There's nothing wrong with having lots of different sexual partners on a casual basis, as long as you treat them all with kindness and courtesy.
I agree that sex with a partner cannot be exactly framed as a 'right' because it's dependent on a partner being available/willing. However, it would be a breach of human rights to, for instance, prevent any member of the general public from masturbating in private, or stop them from seeking willing sexual partners.
Do what works for you, but remember that other people who are more interested in more sexual variety are doing what works for them and not harming you. And they are mostly happier than those who either can't find enough willing sexual partners or who are so guilt-ridden (due to the influence of their own or other people's imaginary friends) that they can't even work out what they might enjoy.