j) RESULT from the OLD TESTAMENT
The standard relationship between man and woman in the OT is monogamy. However, different polygamous relationships (excluding simultaneous polyandry) are tolerated in and regulated by the Torah. Nowhere do we find a commandment of a man having several wives to divorce them just for the reason of not being monogamous.
This already shows you one source of the diversity of opinions on the matter.
a) Those who highlight God's CREATION ORDER of monogamy discredit polygamy and demand of converts to divorce additional wives.
b) Those, who want to continue their polygamous lives and those who hesitate to demand of converts to divorce any of their wives, highlight the INDIRECT TOLERANCE of OT texts to polygamy.