A lot of her behavior was understandable in the show, given what Walt was becoming, but she cheated on her husband who was dying of cancer with her boss, and then kept working with him. That’s pretty inexcusable to me. Later in the show after Walt comes clean about what he’s been doing, he shows Skyler the money and tells her he did it for his family. She takes his money that he earned to leave for his wife and kids, and gives it to the boss that she had an affair with. They both become pretty awful people at different points of the show. Their poor kids have their entire lives torn apart by their psychopathic parents.