bo, your situation sounds so similar to the one I am in it's scary. Considering this, I don't really have much advice since I don't know what to do either. Divorce was never an option (in my head anyway) before, but it seems like the only one now, but I, for some reason, still want to hold on hope that maybe somehow things could improve. It is difficult to talk about commitment as this probably looks different for both yourself and your wife. It sounds to me like you are both still in it physically (by that I mean, both present living in the same house), but not mentally or emotionally. It is easy to say fall in love with her again, but it's not that simple. It's not a switch that you just turn on and off, and, even if you can think about the past good times you have had with her, it is impossible to just overlook and ignore the present situation you both find yourself in.
Does your wife think that there are marital issues that need to be worked on? Is she willing to sit down and talk civilly? My husband is extremely defensive (and, let's be honest, I am too). I have found that then I talk in a certain way, it is better received. Things like, "I wanted to talk to you openly about concerns you may have with the marriage." and then, listen to her answers without defending or putting your guard up. Responses like, "I am hearing you say that...is that what you are saying." "Can you give me examples of what you mean?" "I am sorry, that was not my intention, but I see now how it may have been interpreted as that." "What can I do differently in the future?" And then, also share concerns that you have, but in a certain, non-attacking way. "I am concerned about..." "When you do/say things like...I feel..." "Maybe I am misinterpreting..., so please help me understand what you are really trying to say." "In the future, it would be helpful if you..." Etc. I don't know if this would be helpful or not, but when I approach my husband, I have found that this works better...it doesn't necessarily change the living/marriage situation, but at least it opens communication up a little.
I am sorry you find yourself in this mess, it is awful I understand. I think you are extremely caring and brave for putting yourself out there on PC to really get advice. Bravo. (hugs)