Why my wife wants me to leave?

My name is James and my wife’s name is Jennie and we started dating 13/08/03, things were going great then she got pregnant in 05/04 and we moved in together. On the 22/01/05 she give birth to our son, he was 3 months premature but once we got him home we were a happy family until Jennie started talking to her ex again I didn’t mind until she would piss of up the stairs for hours on the phone, when I asked her what was going on she said it wasn’t how it looked and she‘ll stop talking to him. Then I asked her to marry me for our second yr anniversary and she said yes. Then I joined the army reserves to get some extra cash, but our lives changed on the 25/01/08 when I got a phone call telling me that my brother had killed himself, I took it really bad I was having arguments with my family I just couldn’t get past why he did it, I got the chance to get away with the army for 2wks Jennie didn’t want me to go but I just had 2. When I came back I was feeling even worse everything was really getting to me so I started going online allot got talking to some girl who started sending me pics, when my wife found out it broke her heart plus she was pregnant with our 2nd child, I have never forgiven myself for what I did. On the 11/12/08 she give birth 2 our other son and I thought we put everything behind us we were happy just the 4 of us, then I went away for 2wks in 04/10, everything was going great we moved house in 07/10 and the day after our 5th yr anniversary she started acting strange she didn’t want me touching her or looking at her I asked her why and she told me she wanted me out cause she’d never forgiven me, so we tried working things out she said she just need some space so I ended up volunteering for afghan I go 05/11 but then I found out that she’s been talking to another guy online for almost a yr and that the 2 of them r in love, so now I don’t know what im going to do I love my wife so much and im just trying to get her to go to a marriage councillor but I don’t know what’s going to happen.