Frigid is a word to describe the girl in high school who won’t have sex with you. She always has other plans like her future, college, volunteering, a job. You might use the word to describe a wife that is never interested in sex. I don’t recall ever hearing this word used to describe men. I’m not sure why that is. Plenty of men don’t want to have sex. I’m not sure what you would describe them as.
As a closing thought, isn’t it strange how the frigid girls and wives usually end up the most successful? Maybe we put too much emphasis on sex.