How do you unlove a person?

That’s no longer in love with you, at least that’s how I feel.
Idk if I’m making any sense rn but I’m stuck with wanting to leave the relationship but don’t want to be alone either! I’m so terrified of becoming this lonely ole lady with a bunch of cats. I love him so much but I feel in my heart he doesn’t feel the same for me anymore, I mean he says he loves me but he doesn’t give me what I want, he never did. An when I am away for a few days I get so lonely for him so lonely that I become so depressed which isn’t good. I don’t know what to do.