Why won't a guy talk to you like he should but will others?

I mean I know this guy for years and he don't talk to me at all like he should but will others. I mean he don't act like we are friends. Our definition of friendship is way off. We don't talk online or offline line we should. Sometimes online he pops in and just sit there like he did tonight. Offline he don't even acknowledge me at all. I'm the only one texts to see how he is and all. He never does. Why? I'm not a bad person to know be friends with. He just won't show it to me like he does everyone else. It hurts he don't after all these years. A friend don't do that. I know he does stuff with his others friends like a friend does. But with me, he don't. Why is there something wrong with me that he won't? He tells me that he goes off with the others like he rubs it in. It's wrong and it hurts he does me like this and keep on. Yeah I haven't seen him in 3 yrs that's his fault. That's what I mean. He don't act like a friend to me. Why can someone tell me why and what the problem is? Please help if you can. Thanks if you do.