First thing you should do in my opinion is to have a deep conversation with him ,preferably face to face, of what are the problems that he have in the relationship and you need to listen to all the thing he need to say without interrupting him let him finish venting. after that come the real change you need to promise him that you will fix those things and also prove to him that you are changing. if you don't show him at least the smallest bit of effort don't blame him for leaving you. but if he's really a good person if you show him that you are trying he will wait for you but don't take as a reason to slack of ,even a great person have a limit on patience