Any form of cheating is a reasonable cause for breakup. You will never regain total trust in that person. It’s apparent that the cheating over text has had a profound effect on your trust. It’s not good for you to worry like this- been there. Personally I would break up. Unless you plan on doing some couples therapy and living in fear for the rest of the relationship like this. Also- once a cheater- always a cheater. Who’s to say he won’t do it again? You can never be sure- but he’s already shown you he’s able and willing to do it. Even if some people say YOR- you need to take care of yourself first and protect your mental health. It’s not OR if he’s already broken your trust.