Leave them an "out" so don't feel pressured or cornered.
You will be showing him that a person also moved on from him and that you may be OK without him, and as such is minimise any chances of reconciling with she. https://Vociferousvoid.org/hhh/doku.php?id=how_to_get_you_ex_back_into_you_life_again_-_lea_n_easy_but_ve_y