I really need HELP! What should i do?!?!?!?

I know this guy and we have been talking for a very long time. He is a great guy. I like him a lot that I even think I'm in love with him. The only thing wrong with him is that he does let anyone in. The most that he has ever share with me is that he think he is falling for me. He is always so calm, emotionless and unattached. It is so annoying. He is super sweet and he is would do anything for me. He treats me right and I know he likes me. He doesn't let me know how he feels or what he is thinking. He is still close with his ex-girlfriend and I am so jealous of their relationship. Sometime they seem so good together that I sometime think that they should get back together. She told me that she still like him a lot too. He told me that he wants to be with me. I don't know if I can be with him even thought I love a lot. What should I do about his ex? What should I do about him? I love him!