Saving Your Marriage Tips

I have been married for 21 years and back in 2006, my ex-girfriend contacted me through Classmates.com. I began to e-mail her and also talked to her on the phone (only 5 times in one month). We met for drinks once (she lives out of state). Nothing happened. I did not cheat on my wife, I love her very much, she is my world. I just had not seen my ex in a long time and it was great to catch up on old times. My wife found out about the e-mails but I did not tell her about the phone calls and meeting because it was strictly platonic. Everything occcured in late 2006 and when my wife found out about the e-mails, I immediately stopped all contact with her. Now, my wife has found out about the phone calls and the meeting and she wants to leave me. I feel horrible about conversing with my ex and I cannot convince my wife that I didn’t cheat on her. As a matter of fact, all I talked about with my ex is my wife and our son. My family is my world and I don’t know what to do to save my marriage. I would never do anything like this again and nothing I tell my wife seems to make her feel better about it. Any advice would be appreciated