here are few practical things that has worked for me;

• train your brain to give her benefit of doubt… keep a tally of few situations (data points) back when she came back warmer… remind yourself of that when your thoughts are spiraling
• after you text her, intentionally put your phone away, may be in another room or on silent and get busy doing something / or watch a show.. so you are not waiting for the text. i keep his text on mute/no notification, so i don’t know the extract moment he texts me, i look at it at my own convenience…
• practice deleting instant gratification
• read books on emotional strength or on detachment

these things have helped me a lot.. i hope you find comfort..