My initial take was “casting pearls before swine” i.e. that which is wasted upon the likes of (someone).
Age 62 and spent a good bit of time on the periphery of gay culture in San Francisco during the so called Golden Age before the shit hit the fan. Did not hear this usage or at least forgot it if I did. Guess though that the origin of the idea was indeed the pearls before swine trope with some cross-fertilization with flamboyant pearl necklaces and Hansel and Gretel crumb clues.
I always knew the term as representing words of wisdom or other valued objects. The term has long been part of medical education, going back to at least Dr. William Osler at Johns Hopkins in the late 1800’s. A pearl was a bit of clinical wisdom, handed down from teacher to student.
Never heard it as referring to homosexuality, nor as a hint.
Age 61
I’m 51. Its a reference to “Cast Pearls before swine” which is a Jesus thing, I think. Something about don’t bother trying to educate the willfully and determinedly ignorant. It’s akin to why The Damned’s 5th album was called Strawberries-- giving that material to critics was as big a waste as giving strawberries to swine. But without context it’s hard to say exactly what the OP conversation was about.
I would assume it meant they are either incapable, or stubbornly unwilling, to comprehend the truth. It comes from the Bible, New Testament, Matthew 7:6 “Give not unto dogs that which is sacred; cast not your pearls before swine. If you do, they may trample them under their feet, then turn and rend you."
I’ve never heard it before but when I read the OP I got the correct meaning right away. It probably helps that I know the poster is a gay man and you used the word “Sweetie.”