To inform the other person would make you appear to be crazy, irrational, controlling, and still holding on to the past. This action only makes the narc look like a “great catch”.
The narcissist is already grooming the new person and mirroring back to them the perfect person. The new source of supply will be reluctant to let go of this “image/facade” They will be convinced you are wrong and they’re right, creating a deeper attachment. Of course the new source wouldn’t believe you anyway nor want the information to be true. The narcissist will then use this as ammunition to show how controlling you were by contacting the new person. By doing such, you’re enforcing this notion.
Ultimately know that the new person regardless of what the narc claims, is no better than you.The narcs treatment is the same, so don’t waste your time reinforcing negative behavior. The new person’s outcome will be the same as yours.
So you may ask, what should you do with these raw emotions? Instead, write down your emotions but never send them releasing you from those feelings. Know each of us is responsible for ourselves and not others. Try to do one thing each day just for you. Remember the lesson learned, and no that you can regain a happier healthier outcome for yourself, a narc will never be able to do the same. Pamper yourself! Love yourself because you are worth it!