Okay, so I was going to try to write a series of novella for a set of characters I'd been developing for a few years. Lately, I've decided to discontinue these ideas because of a myriad issues that kept popping up.

So, I've decided to reserve one character for roleplaying, especially 1x1 roleplaying. But, here's where my issue comes up, and I'm not sure if it'll all make sense at first.

In my plans for the novella, my solo character was going to be in a poly relationship with three female characters I'd also developed. However, since I'm now using this solo character for roleplays, especially ones involving romance/erotica, I'm not sure what to do with these three female characters.

I've had ideas about using them as extras: If I find a partner who's interested in a polyamorous romance, I could use one or more of the female characters to fill in the blanks. This is meant to help with character creation, as well as take some of the strain off the both of us from having to manage and play multiple characters, by simply sharing these extra characters.

But, lately, I've been wondering if this is even a viable idea. Especially since that could mean asking my partner to play a premade character, which I've gotten a few rejections over.

At the moment, I'm just seeking food for thought, as I'm trying to decide what to do with a bunch of characters on my hands.

Relationships often change.

You might use them as exs. Or as folks who your Main Character was previously involved with but they're now taking a break. Or moved to being just friends for a bit. Or they had to move for work. Our MC had to move for work.

Or maybe their poly relationship was broken up when one of those characters fell for another character. Whether that relationship is still ongoing or if it ended and they just didn't resume their poly relationship.

They could be good friend characters for potential 1x1 partners. Perhaps they still have a thing for your MC but they're no longer romantically involved. Perhaps they love or hate your 1x1 character. They could either be allies to them, letting them know issues your MC has and supporting them if there are like hard times in the RP...or maybe they're a foil and they tell your 1x1 partner secrets about your MC or otherwise try to stir up trouble.

You might also use them to just show back up after a 1x1 has been going on for awhile, if it starts to slow down or you need a new sort of plot to develop. Right when everything is finally going well in the 1x1 the old flame comes back from let's say London and shows up to the door to catch up on old times, only to run in to your partner.

There's lots of possibility. Are they supportive, antagonistic, or just neutral.

@WanderingDragon
I think you mix up several issues and present them as one. Let’s break down them both, shall we?

Three things you must ask yourself:
1. What is more important: polyamorous plot or this exact set of characters?
2. Would you return a favor of playing a set of characters that somebody else developed to fulfill their dream plot? And wouldn’t you feel used and exploited like a sextoy in process?
3. Why would you even start playing with somebody else, if you’re fixated on your set of characters? Isn’t it settling for less?
Answer honestly, and contemplate why other people are wary of such a proposal. I know I used to pick up roles written by someone else, and those unanimously left me with ashen taste in mouth, because my partner cared more for her token baes and little for my own ideas.

However.
As a game master or a player leading a good fat plot line, a cast of well-developed supporting characters around my main character, NPCs played for partners here and there and otherwise, for me is a good practice of ages. Of course I mostly play my set of kids/exes/friends and business partners and my partners keep theirs and we exchange roles only after permission. Polyamory is tricky, it doesn’t work for majority of people because people are selfish, and the same applies on player’s personal level. You have to employ people who are more CRPG-minded rather than fanfiction/literature oriented, because I see there a deep rift in cognition and deep bonding of player’s self with their character, borderline self insert. The same unsettling fixation on partner/partner’s character tend to be present, too, so beware.