I think you guys will still manage to be friends. It is just a gut feeling, which is weird, because I don't know her or anything. When I saw her pictures from the OW meet album, she actually reminded me of my sister a lot. My sister also wears glasses, and looks to be of a similar height and has a similar face.
I don't know why this is happening, nor do I want the details, but I think I have a good idea from your previous posts. It can't be easy for two people to live together, when one wants to come home and relax, because he is very creative yet is being mentally suffocated at work, and the other is on disability and mostly at home feeling obviously frustrated as anyone would in that situation.
Again I don't know her, but most women I know tend to be more temperamental then men, so I can imagine that being on a disability makes that aspect of it worse (I hope that doesn't sound sexist, but it is just the women I know). The time shared together by two such people has to be full of friction, and from your previous posts, you seem to have identified the reasons, and I have a feeling she has as well, which makes me believe that you both will still be friends after this is over, because the reasons for marrying each other don't seem to have changed much, but it is just the respective circumstances that make it impossible. I have a feeling that both of you recognize that the reasons for liking each other are still there.
I had a buddy who had been living with his girlfriend for 4 years or so, and they were practically married. The problem was that they would fight constantly. You could tell they loved each other, and the reasons for loving each other never changed, but they fought like cats and dogs, and he was miserable. When he talked to me about it, I told him that he should break it off with her, which surprised him. It was almost unthinkable for him, and for many of us (his close friends). When they eventually broke it off a year later, a friend of mine remarked that he had expected them to stay together forever.
Well, he has a new girlfriend now, and loves her deeply and is so happy. She gained some weight after the breakup, but recovered (with his help), and is in a good relationship. They are still very good friends... they just realized they couldn't function as something deeper or something.
And once you are in your own space, and feel more relaxed and everything, I am sure you will be better able mentally to help her move forward.
Anyway, best of luck brother.