I really need advices on how to deal with this.
I had a classmate-turn-friend who I knew for 7 years now. We rarely met since we gratuated but we talk on the phone about once a week. We love shopping and we can talk for an hour about shopping and cosmetics; we also share our beauty secrets. But our family backgrounds are quite opposite. I'm just a simple minded person who came from a simple upper middle class family. She, on the other hand, has always have turmoils in her relationship with men. I feel truly sorry for her; and I always listen to her problems and try to advise her in past years. She has listened but hardly resolved the problems based on my advices. But that was alright with me since they're her own life and her own problems, right?
For some reason, she became a massage therapist and goes out and sleeps with some of her clients although she is a married woman with one daughter. She blamed her husband for not being a good provider, uncontrollably moody and deeply in financial debt. It is disgusting for me, but I said nothing about it since she has similar problems like this before and once I said anything, she would scream at me. I told myself it was her problem and I should never judge her. Her husband now knew about her cheating on him and took her cellphone from her hand when she was talking with me and complain about her with me. Once I told him it was a problem between them, and ask him not to discuss this issue with me anymore, he got upset and asked me not to call his wife any longer.
I have never encountered anything like this in my life. Last night I had a nightmare about it. In my mind, I am thinking I should stop talking to this friend any longer for my own safety. But I still want her to have a better life than this slum life. But I'm afraid that this whole thing can backfire on me. Any advice would be greatly appreciated.

Thank you so much for your advice.