I'm surprised at how many people use texting in therapy. If a therapist uses texting as a tool then her patients are not responsible for any "trouble" she gets in from her husband. It is not your responsibility to maintain the rules and if she hasn't learned her boundaries then I'm sure that is something you two will be working on later.
If you swear it off while in an emotional state~ you might feel another negative emotion when you don't stick to it. There is no shame in needing the contact but don't punish yourself because you realize you might need to establish some boundaries.
Your relationship is growing not crumbling. That's just my opinion~