Why is it so hard???

Why is it so hard to keep a happy relationship? Why is it so difficult to make my boyfriend happy if I love him? Is it possible to be emotionally disabled when it comes to show love and to give yourself to others?
I try, God I try!!! But whenever I want to get close to him, surprise him, make him smile, something goes just wrong. Don't ask! Maybe I'm cursed, maybe I'm emotionally inmature, maybe I'm just too scared of losing him and I get nervious when I have to do something special for him...
I don't know, and it's beggining to bother me, because it's been 14 months and I'm still clumsy and hesitant when he's waiting something from me...
My therapist tried to help me saying that I had unsolved "issues" with my dad, as a male figure, but it wasn't really helpful, so, now I just keep wondering waht to do, what to say and how to get his trust back, how to make him smile whenever he's close to me...