Don't be too hard on yourself sweetie.
It seems we all do this all the time in many areas of our lives. i.e take the easy road.
Maybe it's because life is full of enough challenges for many people right now and we have a hard time justifying taking on any more. And you're right that 'poly' is challenging at the best of times. Sometimes we all have to get down off our high philosophical soapbox and just 'deal' - with life as it currently is.
We all have to pick our battles. At various times some are more important than others. And that's quite fluid.
"Labels" don't matter. Being 'poly' doesn't matter. Being loving does. Trying to make the best outcome from every situation does.
Inside, you know the 'truth' now at least. How that truth will manifest itself in the future is unknown. But the objective hasn't changed.