Cole sounded patetic and not genuine with that sentence. Everytime he told luisa that he would not hurt her, he hurt her in the end. He can't say "i am not going to hurt her the way you hurt me" because he is already doing it even if Luisa doesn't know yet. He already cheated on Luisa and he was indirectly trying to put the blame only on alison by telling her that sentence. And i am pretty sure cole is up to something bad, considering that he didn't tell luisa where he was on wednesday night and he also lied to Alison by telling her that he was home that night which is not true.
He only has to shut up when it's about morality.

Cole and Helen are on the same boat in different ways.