There is no reason for you to have to put up with your resentment of his bad behaviour when he is clearly unwilling to put any effort into bettering the situation. He also doesn't know how to give of himself, and as you said, replaces that personal giving with physical gifts. He is not willing to do any work to make your life with him joyful, or even more tolerable. He allows his friends to demean you and does nothing to defend you. You deserve better.

You can not change him - take that knowledge from someone who has been down that road more than once - he will need to change himself, when or if he ever realizes that what he does is wrong. Learn to recognize qualities that one actually possesses, not qualities you believe you could nurture in them, focusing on what you think could be their potential. You can not instill self-awareness, sensitivity, or willingness to take responsibility for one's actions. This thinking isn't fair to them or to your self - it is not your job. You have been expecting something from a man who simply does not have what you need.

You have grad school to look forward to, and you can't afford to be dealing with these issues while you are working hard to complete your education. Make your exit as quickly and cleanly as possible. You have no responsibility for what shape his life takes once you are gone, and you needn't feel badly for leaving him - he doesn't feel badly for treating you in a manner that would make you want to leave.

I wish you the best of luck.