I've been in a quad going on 5 years now; however, it has changed over time. My partner and I (18 years) formed a quad with another couple (11 years); after about two years they broke up but stayed friends, continued to share finances, and they stayed (individually) lovers with us. So it became more like an N, or 2 Vs connected. We are now undergoing further changes and you can read about this (and other musings) on my blog at www.venusaquarius.com
. I think it is a huge challenge to find partners who all share a willingness and interest in being poly at a sustainable level. However, I know it can be good, it can be challenging and it can work. Good luck!