I think I can stop this.... can you help me?

[Fitz]

Hi All. I have been reading the forums for a few weeks and just decided to join. I have found a lot of the things that I have read to be honest and helpful, and I am hoping for some help with my situation.
I am 38, my wife is 33. we have been together for just over 4 years, married for 1.5, and we have a 3 year old son.
This has been a tough year for my wife, and for myself as well. Her mother was diagnosed with cancer in January and passed away in February. She moved in with us for those 5 weeks and my wife took a leave from work to care for her. I was a great husband and a great help to her during that time. Naturally my wife went through a period of grief, and I was there for her the best that I could, whether it be to give her a hug or listen to her, and I know that she appreciated all that I tried to do.
Fast forward to May of this year, and that is when the serious problems arouse. I was accused of being unfaithful to my wife and naturally she was livid. She was convinced that I had cheated, but I did not. She wanted me to leave, she wanted a divorce. She could not stand to look at me.
I did not want this, so I spent the months of May and June just trying to get her to listen to me. I never cheated, it didnt add up, I was always where I said I was going to be, I always answered her calls and texts, where would I find time to do anything like that? Finally after about 2 months of going through this, she calmed down. I do not think that she was ever convinced that I did not cheat, but I think that she was more convinced that she could not prove anything.
In early July we slowly started talking again, and getting our marriage back on track. We went to marriage counseling, but both counselors that we tried were uneffective, the sessions were more like refereed arguments.
My wife and I started to get alog much better beginning in August. We still had an occasional blowout every 3 or 4 weeks, and her automatic response to that would be to tell me that this is never going to get better and she wants a divorce, and that if it was financially possible she would leave and get her own place. At first these arguments really bothered me and I would attempt to talk to her. But the more we argued like this I began to take it as part of her cycle: when she was mad she would tell me she wants a divorce.
Back in early October she was put on an antidepressant, she was having a hard time with the grief from her mothers passing, and all of the problems that we had been having. She came to me after she got put on medication and she apologized to me. She told me that she could now see that she has been blaming me for all of her problems, when in actuality they had nothing to do with me. She thanked me for sticking by her and assured me that she loved me. That meant a lot to me.
A few weeks later was when things got crazy. I have never questioned her faithfulness to me. But I came home on October 21 and noticed that she had an email account up on the computer screen. It was hers, she had set it up in secrecy. In that email, she had sent one email to one of her friends saying to use this account for any secret stuff. I am not one to snoop, but I found this somewhat alarming. I monitored the email account, and 2 days later my wifes friends wrote back with the phone number and name of a divorce lawyer. I didnt say anything to my wife about knowing about the email account, but I did continue to monitor it. In the meantime my wife and I had been getting along great. We were laughing, going out together, a lot of talk about the future, and it just felt good. In my mind I figured that she had just set that email account up one day when she was angry at me. She had not even logged back into the account until November 7. But when she did she responded to her friends email with the divorce lawyer info, and she wrote "thanks, I will save this for when the time comes". Hmmmm. That very day on 11/7 she also forwarded an email to her secret account from her work email. This was an email that she had written back in July to an old boyfriend. In that email she had confessed her love to him, and told him that she wished that the two of them had a chance together. This guy had finally responded to her on 11/7 and she forwarded the whole email string to her secret account. His response was hard to decipher, he wrote something along the lines of he was sorry to hear she was unhappy in her marriage, and then told her how she was always so beautiful. still I said noting to the wife, because still we were getting along great and my gut told me that nothing was going on. But i continued to monitor her secret email account. on 11/12 she forwarded another email to her secret account from her work email. This one was an article from online about a Walmart store that had just celebrated its 15th year of business. In the article in mentioned the store manager, who just so happened to be a different ex boyfriend of hers. I was thoroughly confused. We had been getting along great, but I had seen with my own eyes that she had been talking about divorce lawyers with her friend, and she had tabs on 2 old boyfriends. Still I said nothing to her. I read DB and DR. I absorbed all of the info, knowing that I might need some help this time.
On 11/14 I called her on my way to work. We were still getting along great at this point. On that call, she had told me that she had gotten ready for work early and taken the backroad, scenic route. I asked her if she had stopped anywhere, and she told me that she had stopped at Walmart, the Walmart that her ex works at. She was unaware that I knew he worked there. I asked her if she had seen anyone she knows there. She said no. Finally I couldnt take it anymore and I told her that i knew everything and she needed to be honest with me.
About the divorce lawyer info, she said that she was talking about that with her friend back wen things werent going well between us.
about the email that she wrote to ex bf #1, she said that she wrote that when she was in a bad place, depressed, and that he had written back and she had just deleted it.
About the Walmart bf, she said that yes, she had gone there to hopefully bump into him, and she did. She said that they chatted for a few minutes about how they have been (they had broken up back in 2006), and they talked about both of their mothers (his had passed recently too), and the way that they had left it was "hey it was nice to see you, take care of yourself", with her giving him her email address in case he ever wanted to reach her. I am not sure how much of that I beleive. She tells me that she never cheated on me and never would, and this was striclty her wanting to see how he was doing.
After I confronted her, she flipped everything on me for snooping. I knew that it was wrong of me to do that, but I felt it was warranted in this situation. She got pissed, told me she wanted a divorce, and then went on to tell me that the reason that she had been contacting these ex's was becasue she still thinks that I cheated on her back in May, and she said that there was an emotional connection missing between us and she wanted a divorce.
She went away for the weekend with my son to visit her grandparents. She called me the next day, she told me that she was sorry that she did what she did, and that she just had a brain fart and would stop. Again she assured me that she had no intention of cheating on me, etc. She told me that she thought that I was too controlling and that the tighter the leash I kept on her the more it made her want to rebel. I do not think I am controlling in the least bit, she takes me asking how her day was as interrogating her.
I am confused as to what to do now. I love my wife and want to keep my marriage and my family together. I know that she loves me, but I am not sure how much damage is already done. Something is not right.
I am the type to always initiate the converstations with her, to always try to fix things and let her know that I love her. But I feel like this time I need to do something else, maybe I had been smothering her.
Would a 180 help my situation? I know that there is still love here, but I feel like it is buried underneath alot of of things. I do not understand why she has been acting out for the past month, especially when we had been getting along so great. And I am doubtful that she will stop this behavior.
It would be nice to hear anyones opinion/advice. I feel that if I dont step up my game and do something now then it is going to be too late.
Her and my son will be home tonight from her grandparents. I have not spoken to her all day. Can anyone help?