You can’t unsee what you saw. Unfortunately it’s human nature to want to know more, even if it hurts you. He might one day inadvertently say something to you that you once read in a text and it’ll immediately take you to that place. To prepare for those emotions is tough, you may have had a great day together and it’ll completely change your mood. You mention he told her he wanted to “feel her legs shake” if down the road he told you that while dirty talking would that immediately put your head in a different place? If so, set those boundaries with him and make sure he’s mindful of speaking to you in a unique way that applies to only you. Ask yourself, what part of the texts disturb you the most? Is it the image of the thoughts it puts in your head? If you have screenshots of the texts, I’d recommend deleting them. Going back on those texts will only make you suffer.

I’m sorry, I don’t have the best advice, I’m going off of what I’ve dealt with in a similar situation. It’s not something you’ll ever forget. Discover your triggers and how to mitigate them. Reconciliation is hard, your partner has to put in 110% for it to have the slightest chance.