Falling out of love -- what can I do?

I'm sorry about your mother. I know must be hard having an unsupportive spouse during this time. They should be the person you rely on the most. Since you have talked to her previously and she improves for a short time, it appears that she is receptive. You may want to consider making a "date" night once a week that the two of you can spend quality time together. Sometimes spouses tend to get so caught up in everyday responsibilities that they forget to make time for one another, which can be a nail in the coffin for a marriage. Also, you may want to consider counseling should that not work. Communication is key. It sounds like you both love each other so don't give up on her yet. Sit her down and tell her your concerns and let her know that you can't live in a loveless marriage. Maybe some issues will be brought out into the open that may help you work through this. Good luck and I wish you the best.