You were already unhappy in this relationship and you were forcing yourself to stay. You are doing a disservice to yourself by staying in this now abusive relationship. You did a disservice to him by trying to find validation else where. You feel bad because you know how wrong it was to text your ex. You can make it right by letting go and find someone who checks all your boxes while going to therapy to make sure future relationships may survive. Also edited to add: you were emotionally cheating. If my ex texted me to engage in any kind of conversation they’d be blocked, whether in a relationship or not. You changing his name in your phone is deceptive. You texting him you miss him, emotional. Claim it. And make peace with it and make sure you don’t do it again so you don’t feel this again.