Hi, Welcome to the forum. I am so sorry you need to be here. It sounds as if your mom has done a real number on herself. That's sad. But, she is a grown-up. She has made her choices. You need to let her destroy herself if that is what she chose.
No one but those of us who have lived it will understand. Your FOO probably won't be supportive but you have to take care of you first. Also don't ever again put out a single penny to help your mom. You have no legal responsibility to do so and if you do it voluntarily you could wind up being on the hook in the future.
Its quiet here since it is a holiday weekend so please be patient. It may be a few days before you get more responses.