She won't listen to anyone (not even her doctor) about her health and refuses to acknowledge her eating problem (even going so far as to claim she "eats nothing" which is so unbelievably ludicrous, I have no words). This is a serious mental disorder, which is not your responsibility to manage and/or resolve. You tried getting her into therapy, that was more than enough help on your part, she refused it, there's nothing more that you can do. She got herself into this mess; she needs to take responsibility for it in order to get herself out of this mess. You've been together for so long that this feels wrong, in a way, but people change and sometimes they're not able to cope with reality. Her not being able to cope with her dad's death triggered this overeating because the grief was (and still is) unbearable. Her avoiding the reality of what she's doing means that she is also avoiding the reality of a huge loss she hasn't dealt with. This is on her shoulders, not yours and her refusal to face anything about her situation makes it impossible to help her. I would move out, get a divorce, start paying attention to my own needs more, slowly let go of her and if she decides to finally take care of herself then great, if not, at least you have your own life now in which you are focused on yourself.