I think there are couples where at least one of the people involved doesn't realize they've settled or that they don't actually love their partner, and that only when they get the perspective of a new relationship with somebody they desire and love more does it dawn on them that they didn't really love or find their prior partner as attractive as they believed they did.

I know one example, and this is only a personal anecdote from people I know, of a girl (fairly run of the mil average looking girl) and her ex boyfriend. He (also quite average looking, kinda resembling Joseph Gordan Levitt) was a nice dude, pretty laid back and chill. And they have a fairly boring looking dynamic but she would say she loved him etc but that she also suspected she was kinda demi sexual. But recently she got together with a new guy, very tall and good looking to the point where I wonder why he even got with her but hey ho, and she is all over him in public and on social media and it's super clear she's proactively besotted with this dude, a whole other level to the last guy.

So I just wonder whether or not people who haven't actually been with somebody they truly desire don't realize they have settled in the past and think they're mundane attraction starved relationship is actually just what love feels like?