Hi i am23year old girl, i am in love for the past 3 years with a boy who lives in another town.?

i love him very much. he also love me. he belongs to a rich affluent family and i belong to a middle cl family. he is the only child of his mother .we both lost our father 2 years ago.problem is this that he has gone abroad this year. although he calls me and care for me but i m feeling that there something in his mind.my mother asking me for marriage ,and whenever i talk to him regarding this, sometimes he says that i wont be able to do as i belong to a diffrent religion and my family will not accept you dont have rich status as we are having. and sometimes he says yes you are mine i will marry you, wait for me , i always force him to talk at home about me, but he always make excuses.but i never understand why he calls me, show his love and care towards me, i love him like a mad, he remains busy in his friends always, i m not saying that he dont love me but he is careless.he is also 23years old.i know his family has many expections from him , they need a girl from their caste, rich and dowry also. i can also provide this. but it seems my boy is not with me.i feel like i will commit suicide. as i cant spend even my 1 sec thinking about him. i dont know what is there in his mind. how can i get to know??? he always says i tod you na i will be there with you but he is also very confused. i have given him everthing to make him happy, even i have physical relationship with him.but i know he never thinks wrong about me. he loves me. he never talks to another girl even in my absence........... still cant understand. please dont consider physical relation can be the reason but please help me