Hopefully you did not bring up the cell phone. You need proof. I initially brought up my suspicion of wife's EA too early, before I had proof (I only had the warning signs). W denied it and tried to throw me off track. Talked about how good friends they were and said she would share their e-mails with me. Then came about 1 planted e-mail a day to her account that she would show me.
The second confrontation went much better. Had proof of text messages with the words I love you going back and forth and more, I had proof from phone records of number of texts and phone calls daily. She initially started denying it and I used the phrase I read on someone else's sitch with "stop, I know all about you and OM, I think at a minimum I deserve the truth." She then immediately caved and admitted to EA. I never showed her any of the proof, just spouted it off the top of my head and quoted some of their texts including one that I would never be able to just come up with if I hadn't read it.
All confronting without proof could do is make them be more secretive. Luckily for me, that wasn't the case. She was careless and I finally got proof and then could draw a boundary which is the only hope of ever getting it to stop (and even that might not do it).
Keep the faith, keep a positive attitude. Don't give up. I'm not an expert by any stretch, I've screwed up more times than I can count and I rely on expert help. My sitch is far, far from a positive ending, but I can say things are a little better. not much, but a little. I can only offer my experience with bringing up an A, having done it the wrong way and the right way and seeing the difference.
M39 W41 Two children WAW bomb dropped 11/7/09 Piecing Aug 10 - Nov 10 No longer piecing...Nov 10 Separation Jan 11 EA ends again Feb 11 Piecing attempt #2, Mar 11