So I guess I see no point in discussing since he refuses to validate my feelings/complaints. Maybe if there was some validation on his part I would want to discuss but since there isn't, these confrontations are just digression.
Have you actually told H about this? I know that it would be so much better if H would realize on his own that validation and empathy are exactly what you need right now (aside from the time and space), but he is a man -- we suck at reading emotional needs!!! We also suck at reading minds , and I'm sure H is no exception here. You might have explained this to him, but maybe you need to beat him over the head with it (kind of like CVA hinted). H needs to hear from you that you want to save this M too (if that's still what you want). H also needs to know what is important to you right now and what will help to save this M, and he needs to firmly hear this from you. Don't cower under his control -- you do hold all of the cards right now and you must put your foot down and spell things out for him. I'm guessing you think that if you have to tell him how to act and interact with you, then it will be forced and won't be from his heart. If this is the case, I would like to say that, sure, maybe it is forced at the moment, but he will come to realize its importance and the validation, empathy, etc, will eventually become quite sincere. But, have no doubt that even the forced validation and empathy comes from the heart, because he is willing to go outside his comfort zone and what he thinks is important to try and save your M. Forced or not, the effort stems from the heart.
Give it a shot. Tell him, "Whether or not you think my feelings aren't right and are unnecessary is beside the point, H. The bottom line is that they are my feelings, and because they are my feelings they are important. If we are going to work on this M, you are going to have to step into my shoes and try to understand where I'm coming from -- feel what I'm feeling. Until you do that and have some respect for me and what I need right now, things will not get any better. If you love me and want to save this M, then this is what I need from you. There is no quick fix to this, H. I wish there was but there isn't. This is going to take time, and I need you to understand and respect this. I'm sorry that it is this way, but that's where I'm at right now."
Have you more or less laid this out for him yet? I think your H really needs to have your needs spelled out to him if he's going to change, and in all honesty he may very well need a legal separation to bring about his epiphany. For my awakening, it took my W leaving me and moving into her apt before I got it. I would at least like to see you tell H what isn't helping in terms of the MC seshs, his time around you, his behavior, etc. I know it feels like it's not sincere change if he doesn't decide on doing it on his own, but if he'll make the effort, it shows that he cares enough to try. He may not understand it, but doing it because you say you need it says a lot IMO.
I just hope you try everything before you throw in the towel, that's all. I respect your decision either way. I know that you are discouraged right now, and don't want to wait for the epiphany, but sometimes leaving a horse in the desert hoping he'll search out and find the nearby waterhole proves to be deadly if he simply thinks you'll be back to get him (lame, on-the-fly analogy).
, and I'm sure H is no exception here. You might have explained this to him, but maybe you need to beat him over the head with it (kind of like CVA hinted). H needs to hear from you that you want to save this M too (if that's still what you want). H also needs to know what is important to you right now and what will help to save this M, and he needs to firmly hear this from you. Don't cower under his control -- you do hold all of the cards right now and you must put your foot down and spell things out for him. I'm guessing you think that if you have to tell him how to act and interact with you, then it will be forced and won't be from his heart. If this is the case, I would like to say that, sure, maybe it is forced at the moment, but he will come to realize its importance and the validation, empathy, etc, will eventually become quite sincere. But, have no doubt that even the forced validation and empathy comes from the heart, because he is willing to go outside his comfort zone and what he thinks is important to try and save your M. Forced or not, the effort stems from the heart. 
