Firstly a bitch is a female dog.
It is also used derogaratively by WOMEN against other WOMEN who are unsupportive of their fellow women for the sake of currying favour with men. It has nothin to do with the accused woman's sex life - she could be a virgin and still be a bitch.
In my culture there is NOTHING IMMORAL about sex between consenting adults. I can have sex with as many different men and/or women on the same day, or even at the same time, as I want and as long as they are all consenting adults there is nothing immoral about it! This is our birthright and nobody may take that from us. So if my culture means you see me as a bitch, then I'm a bitch n I'm proud of it.