My ex and I were mono for 20+ years, and he was v jealous of any feelings I had for anyone else. I felt evil for having a roving eye and causing him pain.
He used to deny he ever felt anything for anyone else. He lied, just to try and make me "behave." Once we finally started exploring being poly, he admitted to imagining sex with every attractive woman he saw...
So, we wasted decades denying those kinds of feelings, lying, hiding, pretending. Lots of "mono" people aren't really mono, they are just acting the way they think they are supposed to act, and because they can't deal with jealousy.
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
me: Mags, 59, living with:
miss pixi, 37