You haven't known discontentment until you've seen an elderly couple like my in-laws who live in the same house while despising each other, yet refusing to divorce because it's against their religion. They don't do anything together, they don't speak beyond the absolute necessities, and they don't sleep in the same bedroom. The husband has been openly cheating on the wife for years (and she has evidence, because the husband of the woman he's cheating with tracked her down and mailed her photographic evidence). She calls my partner all the time lamenting how awful her life is and how she can't wait for him to die so she can be free.

Don't lecture us on the contentment of marriage without acknowledging what the other side of the coin is. This was the reality of marriage before divorce was normalized.