Here's two:
Exodus 21:10
If he takes another wife to himself, he shall not diminish her food, her clothing, or her marital rights.
Deuteronomy 21:15-17
“If a man has two wives, the one loved and the other unloved, and both the loved and the unloved have borne him children, and if the firstborn son belongs to the unloved, then on the day when he assigns his possessions as an inheritance to his sons, he may not treat the son of the loved as the firstborn in preference to the son of the unloved, who is the firstborn, but he shall acknowledge the firstborn, the son of the unloved, by giving him a double portion of all that he has, for he is the first fruits of his strength. The right of the firstborn is his.
here's a Scripture where the Lord told David He'd given all of Sauls wives to him:
2 Samuel 12:8
And I gave you your master's house and your
master's wives into your arms and gave you the house of Israel and of Judah. And if this were too little, I would add to you as much more.
and then there were the Laws about marrying the women captured in battle:
Deuteronomy 21:10-14King James Version (KJV)
10 When thou goest forth to war against thine enemies, and the Lord thy God hath delivered them into thine hands, and thou hast taken them captive,
11 And seest among the captives a beautiful woman, and hast a desire unto her, that thou wouldest have her to thy wife;
12 Then thou shalt bring her home to thine house, and she shall shave her head, and pare her nails;
13 And she shall put the raiment of her captivity from off her, and shall remain in thine house, and bewail her father and her mother a full month: and after that thou shalt go in unto her, and be her husband, and she shall be thy wife.
14 And it shall be, if thou have no delight in her, then thou shalt let her go whither she will; but thou shalt not sell her at all for money, thou shalt not make merchandise of her, because thou hast humbled her.
I've found this to be a little helpful:
tulc(hopes it helps you also)