He never had that opportunity to develope that reflex

 

of longing for your love.

When he was growing up, you satisfied his every need with mateiral things.  So the relationship is

him <--> material <--> you.  He was happy with the material you provided then, and happy with the material he obtained by himself now. 

Is it fair to say that material thing substituted your love then, and he doesn't have much room in his heart for your love now?

Give him a call every three or four weeks, during the time you think he is not busy.  Do not talk about money.  Do not talk about things.  Talk about what you did recently that made you happy.  Ask about events happening in his life.  Show that you are happy because he is happy.  Mail him a package once in a while with things that are symbolic of your love (hand-made or small items of art work he can place in his home.)

Trust the power of mother's love.