I am hesitating about writing this reply because a lot of people may take it in the wrong way. But I have decided that I will still go ahead.
I know this song and it is beautiful. I think that it is great when our spouses give us that feeling that once they are with us, we are a much better person and we can achieve a lot more. There is a limit, though and there is a point where you can start to worship your spouse in the sense that you think that things are only possible with them. (O.K. I said it!) This is not true. All things are possible with God, not spouses.
Even if you are not a religious person, if you project on your spouse the belief that you depend on them so heavily to get through everything it can be too heavy a burden on them. It is too much expectation and this is what your W feels.
Don't get me wrong. My H brings out the very best in me and at first I thought how could I ever go on without him. I would definitely want him to be my H for the rest of my life but if it does not happen I will still go on and survive and thrive at some point. I will depend on God for my strength. I am not preaching to you but you have to find your source of strength and BELIEVE that you can do this.
It is hard. So hard but please, please do not put this type of burden on yourself and your W. She is only human and she will crack under that type of dependency. We all need someone to lean on. No one can be the strong one at all times.It will suffocate her and this seems to have happened.
How have you ever let her lean on you? How did you support her in the past? Think about it and let me know.