What's the best way to tell your ex you can't be friends?

Anonymous
Firstly we've had NC for 2.5 months and she is dating someone else. She text me over the hols and I responded. I now feel worse for talking to her and know I can't handle friendship. I never told her at the time how much she meant to me. I don't want to be friends and just want to forget her. Anyone got tips for doing it without saying why. I don't want to tell her how I feel now as she is dating someone new and I am not comfortable with her knowing this whilst seeing someone else. Basically I want to tell her we can't be friends without having to explain why. How do I do this without coming across like a jerk? And maybe not burning future bridges?
What's the best way to tell your ex you can't be friends?
5 Opinion