Okay. Just… no.
Long-term committed polyamory exists. Please do not paint it as strictly spark-chasing. There are people in this world who don’t classify people into primaries and secondaries — there are people who are able simply to love them past the spark, the limerence. You said you were in a polyamorous relationship for four years? Yeah, mine lasted six and could have gone longer if not for barriers to being able to progress as any other relationship might (to cohabitation, to functioning as a family unit). Love was not the issue. Spark was not the issue. He was free to chase sparks. He was happy with the two of us.
I didn’t leave because I wanted sparks. I left because I knew those barriers would never be lifted, and I wanted the long burn.