So, I’m in a long-term relationship with my loving partner, and everything is good, except for the matters of sex. Suffice it to say, one partner (male) has a very overwhelming sexual drive, while the other (female) needs sex like once a month (and it has always been so throughout life). Partners are monogamous and do not explore options of having a third party.
Can any good advice be derived for such cases? Is there something that can be done to improve things on each side? I would love to hear your advice.

It’s not hot for the other if you clearly aren’t into the sex as well, and they can usually tell. So one person is typically always doomed to suffer.
That is a broad, blanket statement overlooking a constellation of preferences and proclivities. For example: free use, CNC, bored and ignored, to name just a few. Something even more obvious to a person: not getting sex from one’s partner and the lower-drive partner can’t be arsed to do something about it.