This all sounds really really positive, regardless of how your M turns out. Taking it slow seems like the right approach. Do you feel a sense of urgency like your H is pressuring you to take a step forward? If not, it sounds like you are making great progress in your communication with each other on your weekly walks, so as long as those continue, you are still making strides.
Also you made a point early in your thread about allowing him to be irritable. I also take this as a good sign - in that he is in control of his emotions and comfortable enough in expressing his views without regressing into old patterns. Someone who is faking it may seem overly pleasant all the time.
Take all this with a grain of salt... I'm only reacting to your post, and you know your H.
