I'd say it really rather depends on what you mean by "slut."
I consider my wife to be my wife. She an intelligent, educated, strong, confident, sexually open, more-than-a-little-weird woman. I would also say she's a slut... in that she likes sex, enjoys sex with a wide variety of men, enjoys having sex with multiple men at the same time, is a bit kinky and is perfectly comfortable with all of that. However, I don't consider the word "slut" to be pejorative in this sense. I don't think any less of her because she enjoys these things.
In most of the world, women who enjoy sex are demeaned and insulted, while men who do the same are lionized. I reject that out of hand.