It sounds a lot more complicated then it seems, but I want to just put my point of view if I may.
She says she never loved you, yeah ok this could be depression but what if she really never loved you? People can tell you to go to rediculas extents to find her help, but at the end of the day if she never loved you don't you feel that enoughs enough? Look I understand, but she doesn't want help, there for she doesn't want things to change. Maybe a devorce is best for you, so that way she can seek her own help and you can move on with your life without the dreadful tention.
Just putting something from a different point of view, because people seem to think you should be bending over backwards and well this depression thing has been going on even before you met her? So whats going to change now, if she doesn't want to go or want you to go then it doesn't exactly seem like she wants to make an effort.
Before anyone comments "oh you don't know what depression is like", I guarantee you that I most defenitely do. But if she wants a divorce, then it's probably actually best for both of you and now you can both move on with your lives.
Ofcourse, I'm not saying this is in anyway the right thing to do, but after you seek her help and go through all this hard thornyness, will she leave you anyway? or will it make her feel more guilt.