Don’t tell her, show her.
Don’t keep her waiting, hit her up first once in a while.
Don’t assume things by the looks of it, hear her out.
Don’t make her feel unworthy, keep your ex relationships to yourself.
Don’t blame her for questioning, be patient and reassure her.
Don’t raise your voice at her, she’s already at her weakest point when you guys argue.
Don’t beg for her back, when she finds someone else who treats her better than you can.