Haha, my husband has read a bunch of shojo, josei, and yaoi where the couples you'd expect to end up together don't. He usually rages.
And actually a while ago I pitched to him one of my first graphic novel concepts, which was a romance that ended with one party dying and the two never really attained those feelings of mutual romantic love. Needless to say he didn't like it. LOL
But as for me, the one that immediately comes to mind is …
Stranger Things
SPOILERS AHEAD
I was surprised Nancy didn't end up with Jonathan, as that would have been the obvious way to go. I actually kind of like the show sticking to its guns and she stays with her original boyfriend, even though he's kind of an ass. Well, we'll see if it lasts in season 2 I guess.