You're forgetting the part where on her deathbed, she doesn't think about her husband she spent decades with, or her children, or her family at all. She thinks about a random homeless guy she fucked as a rebellious teen.
I remember thinking she had dropped it on accident and felt bad for her when I first saw it as a kid. She made a little "oh!" with a look of what I thought was surprise
At the time titanic came out, romcoms really hit peak it seems. And i watched a bunch of them. Being 14, i had no idea about life in general, and always assumed people get married some time after the movie ends and they found each other. In most movies it's fucking ridiculous. You watch two people fall in love who realistically talked to each other for an hour in real time.