Was Moses A Polygamist?
Some might be surprised to learn that Moses may have been a polygamist. Although we cannot know this for certain, what is fairly certain is that Moses had two wives: 1) Zipporah (Exodus 2:15-16,21 and Exodus 18:1-6 2) and an Ethiopian woman (Numbers 12:1-15). Of course, it is possible that the first wife died before Moses married his second wife. The Bible simply doesn't tell us.

Some have suggested that Zipporah and the Ethiopian woman were one and the same. However, Zipporah was of the tribe of Midian. Genesis 25:1-3 shows that Midian was one of the six sons born unto Abraham by Keturah. Therefore, Zipporah was a descendant of Abraham. Abraham was a descendant of Noah's son Shem, according to Genesis 10:1; 11:11-27. But the Ethiopian woman descended from Cush, who descended from a different son of Noah, Ham (Genesis 10:1,6). Therefore, since Zipporah was a descendent of Noah's son, Shem, and since the Ethiopian woman who was a descendant of Ham, Shem's brother, Zipporah and the Ethiopian woman could not have been the same person. Furthermore, we can determine the timing of Moses' two marriages.

The record of Moses' marriage to the Ethiopian woman is found in Numbers 33:1-49,17, 11:35, and 12:1-16. This is much later than Moses' marriage to Zipporah in recorded in Exodus 2:15,22.