Nobody claimed that gay marriage was going to harm THEIR marriage. It harms the institution of marriage. It adds to the theme that marriage is a joke, and the word can be used to describe any two (or group of) people who want to make their relationship special in some way.
It is worth noting that Rick Santorum, who was excoriated and indeed "cancelled" for saying it, was absolutely correct when he said that the same Constitutional rationale that led the USSC to legalize gay marriage could be used to legalize incest, polygamy, and polyandry. It is only a question of when it happens.
So now we have children born (or adopted) into these bizarre relationships, with hundreds of corrupt "researchers" claiming that they are just as happy and well-adjusted as children born into...marriages. Sell it someplace else.
One thing that gay marriage has done is create a lot of weird divorce cases as they fall apart.
The unspoken aspect of gay marriage is the fact that the majority of gay marriages are lesbians, and THOSE couples have astronomical divorce rates.
"According to the Office for National Statistics, in 2019, 56% of same-sex marriages were between women. However, the divorce rate for lesbians was much higher, with 72% of same-sex divorces in 2019 coming from lesbian couples, about 3 times higher than gay male couples. The lesbian divorce rate was 78% in 2016, 74% in 2017 and 75% in 2018.”