Help me

I love a guy. I love him so much that sometimes i can't imagine anything without him. The thing is we used to be close and i think maybe apart of him used to like me a little too. i just didn't feel that for him at the time. Now we are not as close as we used to be. And i finally realized that he was everything I've ever wanted. I miss him, i miss laying with him, arguing, holding hands. I love him and i can't help it. I think he might have a crush on my bsf but i might be jumping to conclusions bc they have been talking but she says they are just friends. I don't know what to do or how to tell them. Help me