How Many Wives to Have?

Recently I read article about polygamy (not only in eastern countries) and thought that the cons outweigh pros anywhere. I have one husband and need to take all his love and care, only I and nobody else. The thought of sharing all that I have with somebody else makes me sad. I understand that East has polygamy because of the ancient customs but what about other non-eastern countries? What are the premises? Love and passion or interest? Now I am talking not about men but about women. Mostly they are ready to share care and love and be strong, resigned, and physiologically steady.