This is an emotional affair.
Stop the affair first , it is still going on. No matter what she says….
Send a NO Contact Letter , she writes, you read, she mails with you present. Sample No Contact Letters
You need all passwords, email accounts etc, she must delete his details heself, no pressure from you.
Your behaviour in all this is paramount , she must trust she can talk to you.
Then rebuild you marriage Affair Care Coaching: 7 Steps to Rebuilding Your Marriage After the Affair is Ended
Be strong, be kind to her even if you do not feel like it, love her, she has made a mistake, forgive and work together to rebuild your love and trust.
Best wishes to you and your wife..