The important thing you need to do is to make any changes in your own behavior for you — not for him. That’s the true way to make lasting changes. If you are truly unhappy with yourself, then your feelings are only going to be complicated by being in a relationship. Before you can have success in a relationship, you have to be healthy in your own life. And while [i]everyone[/i] has some problems, there are different levels of problems and functionality.
Since you haven’t mentioned what it is about your life that makes you feel unhappy and unsatisfied, I can only tell you that you need to work on yourself to solve this problem. Whatever that means to your situation, you need to do it.
If, on the other hand, the real problem is that you’re fine with your life, but he’s the one who’s unhappy with his own life and is just projecting his own problems onto you — or else he feels you don’t measure up to his standards (whatever they may be), that’s a set of different problems.
So let me know a little more about your situation for more specific advice. Otherwise, remember that until you are happy with yourself, you can’t be happy in a relationship with anyone else.