Why not just make all of them get together with the MC in the beginning? At least that's how I'm going to do my story
My story starts with most of the relationships already established, and then I add more.
To make it real though, you can't have everything work out all the time. Polyamory is magical, but it won't fix everything.
Sometimes, people are simply incompatible and part ways. Sometimes, they have different life goals. Sometimes we can be friends afterwards, and sometimes we drift apart.
Sometimes, our ex-boyfriend hides his meth habit from us for five years before we find out he was doing that shit every time we went to visit our parents because there was something rotten in the fridge every time we came back home, and the ex doesn't normally waste food like that, but meth suppresses the appetite, and we've never personally taken meth, so this baffled us until one day we refused to visit our parents, and his meth habit surfaced. Sometimes, we stay in contact with our ex for about a year and decide we don't want to hear from him again when he calls us on our birthday and we're in bed with someone else and that someone else has to get up for work early the next day, so we don't want our ex calling whenever he damn well pleases.
Sometimes, our boyfriend dies, and we refuse to call him an ex because we never broke up with him before he died. His widow isn't calling him her ex-husband, so we're not calling him our ex-boyfriend. He's her dead husband and our dead boyfriend.
Sometimes, we run off to spend two months in Hawaii with our friend with benefits, and then we don't see him for two more years, and then suddenly he moves in with us, and the next thing we know, we're married and pregnant.
Sometimes, our lover calls us on the phone to tell us how to deal with our morning sickness, and it's good to keep in touch because we haven't seen him since the pandemic started.
Sometimes, our other lover kinda offers to move in with us, and our husband thinks that's a great idea because he perceives our other lover as more financially stable, but he's job hunting at the moment, so . . .
?