I can also relate. I always got crushes during my long marriage. Very strong ones. I always tried to hide it from my (ex) husband, yet he always picked up on it. I'd try to downplay it, but it was impossible to really do so.
Yes, each crush, unacted upon, would eventually run its course, but it was always a bone of contention, because I didnt have the term polyamorous for most of our marriage.
We both tried to hide things from each other about our attractions to others. I don't recommend it. You can hide it in fear of losing him, but in the long run, from my experience, it's better to be brutally honest and authentic to your most intimate partner, or it causes a disconnect which may become a wedge between you two, causing distance and a lack of intimacy, and unfulfillment emotionally and sexually.
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
Mags (poly, F, 61) loving miss pixi (poly, F, 39) since January 2009, living together since 2013
Punk, 42, ex bf, manchild. I've been Punk'd!
"Master," (mono, 34), miss pixi's Dom for 2 years