Yes to the above. I take it none of your mutual friends or family knows what she's been doing? Not saying you should tell them - just wondering.
Jack, alot of posters here have talked about when they were in the same situation as your wife and were 'sexting' people they shouldnt have been. It strikes me that the majority of them here had an attack of concience and stopped or confessed to their OH's and made a go of the relationship. In your situation she was caught out. 3 times isnt it? It would still be going on if you hadnt found out.
So ... she may now be feeling shame and anger at being caught and having to stop AGAIN, on top of her ongoing feelings about your relationship. Thats quite alot of emotions boiling on the pot. They're not all your responsibility though.
My point (i'm getting there) is this - you ARE the injured party here. Also i recon your feelings are likely much more centered around healing the relationship than hers at the moment. But - you cant be everything in this situation and its damaging you to try. You;re trying to keep too many balls in the air i think. By that i mean you have a perfect right to be licking your wounds, being aloof and withdrawn and being the one who needs winning back. Taking your time and taking stock. You cant do that AND tread on egg shells round her, try to be her counceller, her loving husband, her replacement sexting partner (looking back at old thread) and her jailer. By jailer i mean attempting to phisically prevent her contacting John again by removing his number and stressing that your behaviour will drive her to contact him again.
I dont know how your going to do it exactly, but you need to cut yourself some slack here. Saving this relationship is going to have to be a joint effort. You cant do it on your own - and it cant be done without you allowing yourself to be bloody hurt and and angry properly first.
She's behaved apallingly Jack. Lift your head and see that you deserve better. Give this relationship a go, but dont be on your knees.