Don't wait any longer!
Your priorities are in the right place. Jason has a problem with his heart. He either thinks that he can't love anyone except some kind of idealized conception of the perfect woman, or he has hardened his heart to the point where he will never love someone properly.
His last relationship is the perfect example...6 years! And, he has admitted he is repeating the pattern with you.
Jason has his own journey to truly find his own capacity to love someone else. I feel sorry for him.
But you are clearly a caring, loving person who wants what's best for you and your daughter. If a serious committed relationship is what you're after with mutual feelings and a deepening of love, then don't wait...run!
Oh, and don't think you can change him. It won't work.
On some level he's chosen you because he knows it won't work. He's afraid to face true feelings. And if you stay you only convince him that he can get away with the hiding he's doing from himself.