Sounds like he is a confused in his own feelings. One thing to understand is that just because we love someone doesn't mean we are meant to be with them, and loving someone isn't a guarantee a relationship will work.
If he is open to entertaining the idea of getting back together if certain issues get resolved, find out what the issues are and see if he's interested in going to a couples therapist. Sounds like there may be some communication issues is you're not aware of what these problems were. If he's not, then you have your answer. He may be in love with you, but he may also be right in thinking the relationship isn't right for him.
Love isn't the same as rightness for another. How many people love things that are bad for them? Just because we love it doesn't mean it's good for us or what we're meant to have.
If he's not open to trying again and working on these unresolved issues, than you need to let him go. You need to defriend him on facebook, erase his # from your phone, put all your pictures of him in a folder buried away somewhere. You need to completely disconnect all contact from each other in order for you both to move on. Otherwise you'll do what you're doing now, facebook stalk each other, call each other, see each other. That's not getting over each other, and remaining a presence in the others life doesn't allow them the space to get over the other. These days it takes such extensive methods to fully cleanse yourself and your life emotionally of an ex.
It was very selfish of him to get involved with another when he wasn't emotionally available to get involved with another. Getting over a relationship isn't emotional availability and look at what he's putting this poor girl through. She thinks she's investing in someone who isn't really there. How do you think you'd feel if you were this girl?
Fearing being alone at the movies or on a Saturday night is not a good reason to get into a relationship. He needs to deal with his insecurities over being alone. Being by yourself doesn't necessarily mean being alone. He obviously has ideas about what being alone or by himself means or says about himself.
If you're both not willing to fully commit to working out the issues, this may not be the right relationship for either of you. I know you love him, but after the pain subsides, you too can love another, maybe even more.
In the meantime...Figure it out, work on it or move on. Period.
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