Sure, I get that our own feelings are important to us and "love", whatever that is, invokes very strong ones, but why do we care about the feelings of others? In stories, movies, songs, games and basically any form of art humans have ever created, love is frequently a very prominent motif. Why do we care about the feelings of people we don't personally know, who might even be fictional?
One theory could be that we want to learn more about this part of the human condition and looking at different scenarios teaches us how to handle our own feelings. After all, finding a mate is one of the key evolutionary drivers, and thus, very important to us. I have objections, though. First, it's really not that complicated. Love in art can be reduced to very few, ever repeating, patterns, so the amount of information gained seems miniscule. Second, most stories are either fictional or presented in an incomplete manner, so one could question how accurate the information gained even is.
No, let's not betray ourselves, romantic mythology is not made for our conscious mind. We don't consume it to improve our mental model of the world. We consume it for the endocrine response, in the same way we consume certain substances. In layman's terms: because it makes us feel good ... or sad ... or weird ... or ... anything. We like feeling things, and that's ok.
It's that kind of realization that took me way too long. We don't need to rationalize everything. Our rational mind does not need to give its ok to each and ever one of our actions and preferences. Sometimes there is no answer to questions like "why do I like this?", "why do I want this?" or "why did I just do this?". It's the result of physical processes that do not involve our central nervous system and we don't have enough information to completely explain it. All we can do is observe the patterns and try to predict them.
