Living in a kinky girls' flat the issues surrounding poly and it's many permutations never stay out of the conversation for too long. Of the four of us I have the boy interest (though it's probably more accurate to say he has me :) ) and we can play with other people, one girl has a vanilla monogamous boyfriend (which causes all sorts of problems - particularly because she's very minxy and he is horribly possessive), another has a boyfriend but they play and have sex with other people and the fourth was in a poly relationship with a couple.
'Was' being the definitive word above as the last few days have been fraught with the break-up. Things hadn't been good for a while - they alternated between voicing their adoration and ignoring her when life got busy and so the poor girl's been up and down like a yoyo. At a party at the weekend they pretty much ignored her to play with another girl (henceforth to be called skanky ho bag) and talked about skanky ho bag visiting them and being their pet, which understandably really upset lovely flatmate.
All of this got me thinking about how well various dynamics do or don't work. I have several friends who have been badly hurt by being the third in a collapsed poly dynamic. I think the problem is that unless all three people meet at once the original couple have a shared history and tendency to divert to looking after each other when things get tough. You also have the issue of roaming eyes - if they spot something newer and more novel there's a fairly high risk that the third gets pushed away to make room in the cupboard for a new toy. Not pushed out, just pushed away, at which point self-protecting types walk away and take their independence over a dusty corner (aka most of my friends).
Don't get me wrong - I do think poly can work but am not sure about proper poly relationships - I do know people who have them but generally not all dynamics are equal, which seems to help. Please comment if you have your own thoughts! Some friends I have are a couple and have multiple girlfriends and special friends and coordinate it all via complex diaries, a ginormous bed and strict divisions of time - they swear by it. Others keep the emotional stuff monogamous but play and physical things are more flexible. Don't even mention all the various shades of grey!
What's great about our house is that we can talk about these things - so if someone has a problem with a playmate or kink influences relationship issues there are no barred topics. We can convivially discuss increased risk of STIs, problems with bruising between sessions and how to deal with someone's boyfriend wanting to have a threesome with a girl they don't like as we can problems at work or whose turn it is to clean the bathroom. Actually, I think threesomes are easier than the dreaded cleaning chat!
Thoughts, insights or experiences very welcome. I think it is quite an individual thing and dynamics very much depend on the personalities involved. What I know I don't like is people hurting my friends. The question is - is it pleasure doubled or sorrow doubled?