Your ex is your past, and no part of your future relationship. Learn to resist the temptation to bring up ex-talk or compare any new date to an old flame.
Everyone has baggage, but not everyone let's it affect the here and now. No matter what, don't bring up exs on your first few dates. Even if she mentions Mr Yesterday, just acknowledge what she said and switch topics. In this way, you don't let your ex control your future and you can start on a new path.