I think you are doing the right thing by spending time with a therapist for yourself. When a partner is not taking these steps to reach out for help, then the only thing you can do is make it a point that you don't make that same mistake.

A person that is behaving like your wife is now is simply drawing you into whatever her possibly toxic ways of dealing with her challenges might be because she is not getting the right help to help her from making some major mistakes driven by her confused emotions. Working with a therapist is important because one has to talk about how they are "feeling" and learn what outside factors are contributing to these feelings, and what part the person themselves is contributing to these challenging feelings.