I have been reading your stitch and I am so sorry that you are in such an incredible amount of pain right now. One thing I noticed is that you seem to want someone to answer why you should continue to do this. I'll give you two good reasons: your children.
However, I know you don't want to stay married just so your children have parents that are still together. You want a healthy R. Well, your children need to see what a healthy R looks like too. Think about the kind of marriage you and H are modeling for them right now (I know you are upholding your end of trying to change so I hear you). The reason for this statement is I wonder what kind of marriage your husband's folks have. Is he just playing out the role that was modeled for him? If so, is this the type of marriage you want your children to have down the line?
I was thinking it might be a good idea to edit your week in the life and even add some thoughts like, "at this point I was wishing you had done X" and show it to hubby and say, "Is this really the life you want?" Quite frankly, what you wrote was depressing and made me start to keep track of my interactions. LL, you can't keep this kind of life up anymore so now let's really get down to work and see what we can do to help. I'm game, are you?