it human nature to miss someone who meant something to you at one time. it also could be that you miss having someone. you were in a serious enough relationship to live together so obviously you cared about each other. If his hobbies are more important than human contact especially a girlfriend, then forget him. Is not worth it. I know what you are going through (i was in a relationship with someone who was emotionally numb/wounded from his past and I was the LAST thing on his priority list)

I wish the best for you!!!!