In the six interview tapes played to the court yesterday Ms Stewart (47) also told police:
Ms Stewart told the police the pair had talked about carrying out the killings but she added there was nothing in it for her.
"I had nothing to gain. I had nothing to gain by him doing that. I didn't have anything to gain.
"I wasn't very good in my marriage but I had nothing against Trevor. We had good times. There wasn't a problem but I had nothing to gain," she said.
"Obviously he (Howell) had other plans for himself. But it wasn't including me. In one way he thought maybe I would go with him and get married. There was no intention of that. I never said I would marry him, never."
She also told police that the relationship, after the deaths, was not natural or normal. She said she wanted their sexual relationship to stop but Howell was frustrated and he wanted to make her more relaxed.
"It was so strained. I didn't want him. He scared me. I didn't want anything to do with him," she said.
It was years, she went on, before she ever went near the row of houses in Castlerock, known as the Twelve Apostles, where the bodies were found.