"Physical attractions are common, but a mental connection is rare."
First of all, don't ever think he belongs to you. he used to love somebody else, so he might love someone else in the future other than you. but if he loves you now, does it really matter? knowing that you might lose him one day, try your very best to love him wholly not just partially. you may not be able to measure how much he loves you, but as long as he is there for you in your entire journey of life, good or bad, that alone defines how much he feels for you. a lot is enough. and a lot is more than anything worth. don't try to change him, don't make him feel less special than any other guys and don't expect much from him. he is not perfect, and so are you. tell him that you miss him, but be silent on certain days to make him return your love. make him want you, not you wanting him. you may not be his entire life, but a huge part of his heart is reserved for you, and you are the only one that can break it. smile when he is happy, listen to his problems when he is sad, and be mad at him when he does wrong. most importantly, love him with all your will.