The Bible makes it abundantly clear that people have been messing up God's Laws ever since the very first Law. That some tried polygamy does not change the very clear, and repeated, insistence: For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh
There are no options for 2 men, 2 women, polygamy...or divorce without infidelity. Obviously, people don't manage this well...