Hello poly person here. A year ago I was in a polycule that imploded and I lost several partners. What was left of the part I was still involved in couldn’t absorb the emotional shock so it slowly dissolved over 6 months. Because of how much time was tied up with partners, my friend group was basically the more casual partners. Basically my entire social circle fell out from under me. You are correct, it was distinctly not fun, it has caused me immense damage