Cheating fantasy

My husband cheated on me once it was one kiss and he told me tight away so i gave him another chance. He now has admitted that he fantasises about getting with other people. He said he will never act on it or hurt me again but i dont know what to think. He has other fantasises about swinging etc but knows i will never do that and accepts that. Can i trust him? Is this normal behaviour for men to fantasise about other women????