Her problems aren't the pounds or the spending. Those are just symptoms of the bigger problem.
It's wonderful you're supportive of her. You're a great guy& a loving spouse. It sounds like you're doing all you can for her.
The thing is that she will only get better if SHE wants to. She's got to want to change. She's got to want the help. She may never change. And the hard part is if you remind her she needs help with these things, she may not be ready to hear it. If she's not ready, she might react with anger, more depression, and/or an escalation in the harmful behaviors. The best you ca do is make help available and hope she takes it.
Suggestions:
Ask if she'll take an exercise class with you. Make the issue about your fitness, not her weight. It's been shown that regular exercise just 3-5 times a week lifts moods. Can she start talking 30 minute walks with you each evening?
If she opens up to you and says she's feeling depressed, offer to find the money for a therapist. I am not saying that will solve all her problems, but for some people talking out their issues with a trained professional helps the person discover things about themselves.
She may need to make some major changes in her life. Something is making her feel extremely insecure and unworthy. Maybe you can think on what that might be, and then work to make a change in both your lives.
I wish you the best of luck !