Is it time to just move on?

Girlfriend of 4 years cheated on me with a male friend during the first year even though i told her to stay away. When I lived with her, and left for work, she bolted for her boy toy for 12 months, going to help while i went to work. I found out and called on her on it. She stopped. Fast forward 3 years later. She got stage 4 cancer, nearly died. I covered all her cancer treatments 200k and covered her rent. She recovered. I then had my brother die of liver failure and a cousin pass away and then had job loss. Went into major depression. Drank alot, but trying to recover. She is upset with me having alcohol a few times a week, but smokes pot daily. and has now threaten to just end things.Im not perfect of course, but thinking i should just move on? So it was okay when she was a hot mess, but im struggling and she wants to leave? Thoughts