I hate the 'victim mentality' but I do feel a little used because now W is feeling a little better and can just throw me away now that she doesn't need me as much.
Don't choose to be a victim then (easier said than done, I know). In a loving way, be glad that she is better.
If she "throws you away," let it be her loss. Be the best Spartan than you can, as that is the main thing you can control. You are doing pretty well. Keep it going forward!