Your thread inspired me to create one of my own
, asking for advice from the other side of the fence, being in a poly relationship but missing the focus that came with monogamy.
I tend to feel like no amount of additional relationships can really make up for people having to divide their attention among lovers, at least for me, being someone that wants to constantly be with my lover and focus on shared activities with the main time apart being when we have to be separate for work. My wife Ginko and I have been very compatible in this preference, though opening up to dating other people necessarily changed that a bit.
Polyamory seems to work better for people that need a bit more time to do their own thing. My wife's boyfriend J would feel crowded if he got as much attention from my wife as I do, while I find myself missing the level of attention I received when it was just the two of us. Someone I spoke to Friday night was telling me that he'd much rather be someone's 2nd or 3rd priority than their first. I could see polyamory working well for him.