I'm solo poly, and I think it's awesome. Although I have definitely had some difficult and bitter experiences (like what Atlantis described) in the past, I have been lucky to arrive at an arrangement that is working really well. I'll share it so you can get a sense of some possibilities for what solo poly can look like.
My partner Elijah and I have been involved with each other for almost 8 years. We've decided at this point that we are life partners--but we will never live together, or legally marry. Neither of us have or want children. We live kind of far apart (almost 2 hours) but we are both very happy with our respective living arrangements. It would be nice to live closer to each other someday, but that would mean at least one of us having a different job (or a terrible commute).
I love living in the country. In my early 30s, I happily moved back to my childhood home in a rural town, got a job in a small city nearby, and took over co-owning the house with my parents. My dad has Parkinson's, my mom needed help, they wanted to stay in their large house which needs a lot of work, and I couldn't afford to live on my own (at least, not in a quiet, woodsy area). So, I've been building a happy life as an adult sharing a home with my parents, dealing with eldercare and house repairs, but able to have my own space and the solitary time I crave. (Plus, it was an idyllic location for my dog, although she died this year).
Meanwhile, I began dating Elijah casually. He lives in a big city almost 2 hours away. He is very much a city person, which is one of the many reasons we are not compatible to live together. At the time I met him, I was on the rebound from a terrible breakup and trying to figure out my solo poly identity. I really just wanted casual sex at the time. But Elijah and I very quickly became good friends (well, friends who have a lot sex!). We got along fantastically, and were on the same page about non-monogamy / poly/ relationship anarchy. Eventually we fell in love, but we weren't planning on it, and it seemed more of a progression of our friendship than of the sexual aspect, somehow.
Anyway, throughout the whole time, we talked constantly about what we wanted and how it would work. The logistics of the distance between our houses can be daunting and tiring sometimes. But the living apart has always been great for both of us.
Elijah has always lived in an apartment with roommates. Last year his roommates moved out and he lived alone, but it wasn't affordable and he gets lonely (he's more of a relationship anarchist than solo poly). Then a friend experiencing a breakup moved in with him--they get along fantastically as housemates and have become sort of best friends/platonic family. She's also poly, has several partners, and after her breakup has decided to keep her living arrangements separate from her dating relationships. (Which is essentially what solo poly is).
So, Elijah has a fun roommate who might be his permanent platonic nesting-mate. (I like her, but I would be very annoyed if I had to live with her! She is talkative and extroverted--just like Elijah!)
In terms of poly, Elijah and I have never been exclusive. Nor have we ever achieved a state of being "content with the partners we have now." Nothing else has worked out for me, and I've been too busy to do much dating, although I'd like another partner. Meanwhile, Elijah has a very active dating/sex life. He is super extroverted with a very high sex drive, and is very kinky. He's had many various partners over the years. Currently he has another steady partner of a few months, who is also solo poly. And he has a "comet" partner who lives across the country but visits his area for work every few months, so they see each other for a weekend a few times a year. And recently he's had some dates with someone who might become a regular kink/play partner.
From my perspective, this all works great because I don't live with Elijah. Even if we had separate bedrooms, I would be annoyed by all these metamours in the common space. Plus all the screaming would keep me up at night
My point is, being solo is actually a VERY effective way of doing polyamory. I think that point often gets lost when poly people discuss solo poly. Not living together eliminates half the problems and almost all of the hierarchy, if you ask me.
It seems like when the topic of solo poly comes up, there are always poly people popping up to say "Well I guess that works for SOME people but I could never do it!" or "I know one person who is solo poly and they are very selfish so now I am skeptical of solo poly!" Which is obnoxious, and also funny because that's EXACTLY what many mono people say about polyamory!
So, I would like to see more polyamorous people chilling out about the topic of solo poly. Having separate living spaces and separate finances is a GREAT way to do poly.
Solo poly, for me, is really just basing poly on being an individual rather than being a couple, and forming connections between independent individuals. (It's fine to want to be a couple, and in fact a very succinct definition of polyamory is "forming couples with more than one person," but there are other ways to do poly, for sure).
For the OP, I was in your shoes when I was starting out. It was very hard to define what I wanted. Especially because I was essentially "single and dating" and trying to figure how that was, or was not, similar to being solo poly. I was drawn to solo poly because I liked being single and dating non-exclusively VERY much. But at first I thought I would have to avoid falling in love & avoid having "serious" relationships if I wanted to keep doing it! And mainstream mono men quickly abandoned me for "real" relationships
Now I realize that love and partnership is possible while still being solo. I can date other people as much or as little as I want. I have a serious partner who loves me. We talk every day, but he doesn't have to be involved in my daily life (which would irritate me and bore him). He is my emergency contact. He spent a day in the hospital with me (and my mom) last year when I had surgery. He would take care of me if I had an emergency, and vice versa. He comes to my family events. He visits periodically to help my parents with stuff, which he calls his "son-in-law duties"

but he doesn't have to be involved in my parents' daily eldercare.
In fact, he's visiting later today to help my parents with a project. But he's going to be late because he spent this morning helping my metamour (the other solo poly lady) find new housing, which was kind of an unexpected emergency for her. I think he may be providing some emergency financial help to her, which he doesn't need my permission for because we're solo and it's not my business! So, this an example of 3 solo poly people being supportive of each other, and everything is working great.
One final bit of advice for the OP: I found that the key to being solo poly was to find people who understood what I was looking for and were looking for the same thing. People who value friendship more than leaping into a serious romantic commitment right away. People who are independent and/or very solitary. People who do solo poly or relationship anarchy themselves.
Although I theoretically wouldn't mind being a married poly person's secondary--I could have my own life & my own independence--I found I just didn't have much in common with people who decided to get married. I was, after all, looking for an ALTERNATIVE to marriage. And I found it
