Largely positive experience thus far: my current relationship is technically poly, though so far it's mostly been limited to when one of us is out of town for a week or more. General rule is "anything goes as long as you're safe and it doesn't cut into the time we have with each other." Travel (I'm a consultant) is one obvious case, but we live far enough apart that it's hard to see each other except on weekends. She's had one fling with an old fuckbuddy mid-week while we were both in our respective hometowns; I so far have not (only when traveling) but have considered it.
When we are with each other we have largely acted monogamous so far, and things may change if she moves closer (as she is planning to do). We have discussed (her suggestion) adding a third person for a fling, though. We appear to have implicitly rejected expanding the primary circle. Current relationship age is over seven months and this has been the rule since the first month.
Related article: Polyhacking
Note: This article was posted earlier for less than a day but accidentally deleted.
Although polyamory isn't one of the "official" topics of LW interest (human cognition, AI, probability, etc...), this is the only community I'm part of where I expect a sufficiently high number of members to have experience with it to give useful feedback.
If you go looking for advice or articles about polyamory on the internet, you mostly get stuff written by polyamorists that are happy with their decisions. Is this selection bias? Where are the people whose relationships (or social lives, out anything) got damaged or ruined by experimenting with Consensual Non-Monogamy?
I'm posting this hoping for feedback, negative AND positive, on experiences with polyamory. I considered putting this in an Open Thread, but it occurred to me that many other LW readers might be interested in whether polyamory has drawbacks they need to be aware of. If you have experience with CNM (including first-hand witnessing, which has the added bonus of not requiring you to out yourself while still participating in the dialogue), please comment with your overall impression and as much detail as you would like to include (I am also putting my experiences there rather than in this post). If you've seen multiple poly relationships, multiple comments would make tallying slightly easier. I will try to upvote people who feed me data, a la LW surveys. If there are sufficient comments, I will periodically go through them and post a rough ratio of good to bad experiences at the bottom of this article.
PSA: The Username account is available for use by any who wish to remain anonymous. The password is left as an exercise for the reader. Hat tip... Username.