Most of the romantic stories end with the couple marrying and having children. Why?

I understand that this trope is incredibly popular, but whenever I see this in the tags, reviews or description I don’t even start to read the book, however appealing it might have been in the first place. I feel like with this turn of events both the readers and especially the characters lose something important that I can’t really pinpoint. When it comes to fanfiction, it feels forced and out of character. I know the story needs some sort of closure, but I simply don’t like the idea of the characters settling down and living happily ever after. I have never been a fan of happy endings.
Maybe I’m alone with this, but marriage, pregnancy and having children is a triggering topic for me. I think you can live happily with your partner without doing all of the above, so why do authors feel it necessary to add these elements?

What are your thoughts on this? Do you like romance stories ending the good ol’ way?

by Just-Ad-8050