> they're not separate, living, independant entities

It's really irrelevant. Does it matter whether the object of one's affections is real or not? Alive or not?

If your lover dies, she's dead but you still love her even though she doesn't exist anymore.

You can love someone you've never met or talked to, a stranger on the train or a celebrity, even though the idea you have is a construct in your head or of his PR agent.

Maybe you would gush over a sweet talker in an internet chat room, until you find out he's thirteen year old kid with a severe case of acne who was copypasting lines out of pulp romance novels in an effort to get your to send a picture of your boobs.

A lonely man will love his mail-order sex doll with the vagina that detaches for easy cleaning, and when a gynoid prostitute is created, you can be sure someone will love that heartless appliance.

There is no invisible connection that two people in love have, it's not abnormal when it only one of them feel it, and if the object of your affection is only as real as the glossy magazine it's printed on, who gives a shit.
It's just the birds and the bees. Quite literally.