You said you recommend he sees a therapist, but are you seeing one yourself? I think you’d greatly benefit from seeing one as there are many issues you might want to explore.

Why are you willing to put yourself through pain turmoil in attempts to completely change someone else after only 6 months of knowing him? Why are you willing to accept disrespect? Do you not think you deserve better than this? Why do you trust words more than actions? Why do you focus on his promising words rather than his unloving, cold and disrespectful actions?

If you don’t address it now, next man and next relationship might be just like this one. I’d not worry about him getting better but would focus on yourself getting better. Better in recognizing that trying to fundamentally change someone isn’t a foundation for a healthy relationship and pursuing unavailable man is not healthy

you deserve much better for yourself than this