I've only just read your post and my heart goes out to you: it really does. The advice that the others have given is the best and I can't add to that except to agree that a lawyer is the best bet: when you are in such emotional turmoil you need the help of someone who can approach matters in a distant and calculating way… you mentioned a legal precedent which should hopefully work in your favour.
You also mentioned clichés, well, among my female friends and acquaintances an alarming number have found themselves in a similar situation to yours, (minus the complication of MS, of course), and it is staggering to hear how the departing husbands do the same things, act in the same way, and even say almost exactly the same words as each other. It sometimes sounds as if they are all following a script: (" I can't take this any more"… blah, blah, blah…).
But, even though he was there to support you before, remember it is you who has dealt with the devastating emotions of having MS, and if you were strong enough to get through that you will, eventually, come out of this,