Are you not able to express this to him? It is important you share with him the changes you see happening. If he choose to do nothing that is his problem and you have to decide how long you are willing to remain with such a negative person. Sometimes it is best to love from far away.

I think this comes down to your boundaries and confidence in your decisions. He is the only only one who can change himself and he seems to accept his current state without any desire to change it. Only you can determine what is enough negativity before moving on. Life is to short to be mired in negativity. Your thoughts create your reality….. I like to keep it on the positive side personally and get really bummed by negative people.