The only thing that should matter in marriage is love. Even after the Supreme Court had ruled that the same-sex marriages were recognised nationwide, the struggle does not end there. America is. When gay couples want to raise children, they will adopt, which increases the adoption rate. However, other nations are considerably remaining orthodox, where they dispose the idea of same-sex relationships, not to mention not allowing gay couples to marry. It allows same-sex relationships to be under the purview of the law. Society also plays a big part in the gay marriage legalization process.
According to them, gay marriage or the law legalizing it would end injustice on a considerable section of humanity.
If one is all for adopting children, this is a pro. Homosexuality is illegal in many countries. Second, even if we concede for the sake of discussion that a stable, loving male-female couple is the gold standard for parenting, it's otherwise offensive to deny those who fall short of the gold standard the right to marry.
Thus, proposals to legalize multiple-partner marriage should be considered separately from legislations with regards to single-partner marriage.