Why Can't A Muslim Woman Have Four Husbands?

Non-Muslim: Why Muslim men are allowed to have up to 4 wives but Muslim women are not allowed to have up to 4 husbands?

Muslim: Modern science tells us that if a woman has sex with multiple men, then both the woman and the men have chance to get AIDS and other sexual transmitted diseases. But, if a man has sex with multiple women, then neither the man nor the women have a chance to get AIDS and other sexual transmitted diseases. This is why Muslim men are allowed to have up to 4 spouses at a time but Muslim women are not.