Can love exist without a relationship?

I have liked a girl in my ICT class for almost a year. It started out as a crush, in which i couldn't speak to her, and then then it got deeper but, and was probably a deep crush or limerence. Now i'm sure i might be in love with her, because its nothing i've ever felt before, and i'm not as obsessed with her, as before.I love her but its more calm but still manic, and it just feels great. She doesn't know i love her, and i dont know if she loves me. People always talk about love in a relationship, or love with just one person, but can love exist for another without a relationship?