Love is the art of letting go. And no one has explained this better to us than Doctor Stephen Strange. He watched Christine getting married in the multiverse, he proclaimed his undying love for her in another.
And that is love. To let go over and over again. Because you can't force someone to feel the same for you.
Whenever you do think of them, think of them with love and light and wish them the best. There's no point in forcing, chasing or begging someone for their time and attention.
Love simply is. It's either there or it isn't. It's as simple as that. So cry over that "almost-person", drown yourself with an entire bottle of Bailey's, talk about him or her until kingdom come with all your best friends, but ultimately let go.
For only if you let go, do you allow your heart and lives' doors to be flung open again to be filled with the right person.
I lived a Shakespearen sonnet with my late husband. To lose someone you're still in love with it and thrive after that person's long gone, now that's a love story for the books as well.
Let go my friend, let go. It's the only happy conclusion for you and whoever it is, that you are fantasizing about.