Do all MEN masturbate to other women while in relationships???

Some guys were telling me that ALL men masturbate to other women WHILE in relationships!! And if not they're "saints"!! I don't masturbate to thoughts and images of other men!! If some other man pops up, I either stop or I take out a photo of my BF or think about him, and him ONLY! It would hurt me so much if my boyfriend thought about other women while masturbating! Please tell me that there are some good, honest men out there!!