What if you spend your life waiting and he never changes? You already spent 3 years hoping he would change and he hasn't.

Make decisions with the partner you actually have, not the one you *wished* you had. Otherwise, you are wasting your time and wasting your life.

If you do decide to stay and he does not change, then you have to accept your decision. He will not be the one at fault or the one to blame for not being who you want him to be.