Have you ever looked at a couple and thought: yuck! Why is he with her? Why is she with her? How do they have this love and I don't? Or what does he see in him? How can two people like that find anything to love in each other?
Love is a transformation. Everybody who's inside it knows about that transformation.
You can't help but look at the one you love as if they're the most beautiful, wonderful, best person on the planet. It's not blindness. Your vision has transformed -- and gotten better.
If you get a chance, read one of the best, very shortest of stories I've ever read. By Guy de Maupassant, who has probably influenced me as a writer more than any other writer out there.
Here's the story:
Go read "Love - Three Pages from a Sportsman's Notebook" by Guy de Maupassant.
Read more by de Maupassant. His observations of human nature were astounding, and his short fiction has not been matched by any modern writer, in my opinion.