Serial liar Iris is.
In her mind, she was a great wife who was always there for her husband, no matter what. A terrible feeling washed over her as she considered the entire scenario. As a result of having spent so many nights on her own, she was unable to bear the loneliness any longer.
Initially, she was worried about how this might affect the two of their relationship. All the way through the show, she was flawless. In contrast, she could not outsmart him for long periods of time. It’s impossible that she’d be so careless. Thomas was not going to let her off the hook for what she had done.