This will probably be rambly as 
has been had. Long term user but have name changed.
After researching and deciding upon it in the measured, slow and mutual way that is advised, my ex and I entered into an open relationship. We were both fully on board with the theory behind ethical non-monogamy and, looking back, were actually quite smug about how enlightened we were compared to other couples who just cheated on each other or put up with cheating. It was probably more me that instigated it than my ex but it was 55/45 rather than 90/10 iyswim.
The reality was an abject shitshow of misery, mistrust, resentment and jealousy that just accelerated our demise as a couple. As much as my brain was willing, my heart just couldn't bear it. Initially I treated the problems as social conditioning that just needed to be broken down but the emotional responses were just too strong and ultimately insurmountable.
Fast forward 4 years and we're amicably split, both in new relationships and now I find the very idea of non-monogamy absolutely anathema (not judging anyone else, I know it works for lots of people!) to me.
I have gone from being an anti-marriage, ethical non-monogamist to being a sickeningly loved up one man woman who, against all feminist ideals, would love for her DP to propose. I still hate concepts such as 'The One' and the idea that once you commit to someone you stop finding others attractive but I just know now, based on my previous experiences and mistakes, that I would never jeopardise something as valuable as I have with DP for anything in the world let alone a fumble with a stranger.
I'm thinking about all this as I'm watching You Me Her on Netflix with a mixture of horror and fascination. Having to meet the emotional and sexual needs of two people just seems like FAR too much work for my lazy ass.
Has anyone else bought into the theoretical side of non-monogamy/polyamory but found the actualisation a problem?
Or has anyone experienced similar issues and overcome them in terms of making non-monogamy work? I'm genuinely interested in the subject.