I wonder if it's because you associate the concept of promiscuity with the behaviours and attitudes of people who treat sex as a trophy and a bragging right.

There's a big difference between someone who likes what they like and does it when they can in their own bedroom, and someone who uses manipulative tactics to have as much sex as they can and brag about it as though that makes them a winner at something, acting superior.

Growing up in a society that reinforces that behaviour (specifically, in men) has probably meant that the two concepts are linked, and your feelings towards one are the same as the other.

I'm a certified slut and that type of "sex as a conquest" behaviour feels gross to me too, and if that was the only way to have casual sex, I'd never have casual sex ever again, even though I like sex.

I think because I'm not a man, it was easier for me to separate the two concepts. If anything, I was shamed for promiscuity, so it helped me to explore what's right for me with an attitude of "who cares what society thinks about my sex life".

Basically, if OP has sex and doesn't brag about it, did he still enjoy it? Because sometimes I think guys like this don't enjoy the sex for the sex, they want it for the status. And that's whack.