Moving on is hard. It is easy to say forget about your ex and move on. I remember saying the same thing to my ex when she told me she how she'd still think and dream about her ex. I guess I never really understood at the time, because sometimes I find myself thinking and dreaming about my ex even though we broke up many moon cycles ago.
My only suggestion that I can think of, is to think positive. As much as you loved your ex, your ex cheated on you, and he will probably continue to cheat. I guess it is also a learning experience. You deserve better!
