Yep! In my experience alone it was that they thought with their dicks and nothing more. I am always a good woman to my man yet I was still cheated on. I don't think I am nasty either, but it sure messes with your self esteem when you wonder what you did to deserve it. In all cases I could have got revenge and cheated back, but I couldn't do it. I know how much it hurt and I would not wish that hurt on anyone.
My ex denied denied denied for years. He finally came out and admit that he did after I was long gone. I guess he thought the truth would bring me back, but it didn't. He didn't know what he had until I was gone.