If you had any clue about biology and evolution, you'd probably understand by yourself why chastity is valued in society. But clearly you don't.
But I'll make it simple for you: chastity is valued because hoes sleep around with other men.
Both men and women are biologically driven to spread their DNA to the next generation. A woman has the guarantee that her child has her DNA. A man doesn't have the guarantee that the child born by his wife is his, unless she was a virgin before he fucked her. And even then it's not 100% guarantee, but it's the best a man had before DNA testing was invented.
