Progress update:

We were making dinner together & my fiance asked me what I thought that she needed to work on with herself. I told her that I thought that she was doing well with many aspects of her part in the relationship post discovery/serious discussion.

We discussed how things were when she wanted to break up. She then admitted that OM was trying to influence her even then to abandon the relationship & what we had. She also admitted that rather choosing to work on things with us, she was allowing OM to do so (wanting the escape). She had a look of regret for what she did in her eyes. She reiterated that she will never speak to him again & that their friendship is over.

She also thanked me for sending the NC email. She explained that if she had done so, OM would have sent more manipulative & mean messages to her. I told her that I thought that he preys on women's vulnerabilities & weaknesses.

She again apologized for what I had to go through & that she wished that it never happened. We then discussed how great things are going for us & how got back on track with our hopes, dreams & marriage plans.

I then told her that I am not perfect & asked if there was anything that I needed to work on. She thought for a moment & then said that I have fixed the issues that she had & am meeting all of her EN's (spending time with her, appreciating her, not isolating myself in my office, working on/fixing the house, etc.)

I understand why many of you are concerned but things are better. My fiance has been very open about what happened & why & how is will never happen again. All of my anxiety about the sitch is gone.

From here on out I look forward to the future. Thank you all for your advice & support.

Excellent radio clip where Dr. Harley tells what an engaged couple should do to prepare for marriage. Radio Clip at 6:45 mark talking what engaed couples should do before M! POJA

Another good clip at the 7:45 mark where Dr. Harley says how long should you be together before M. Radio clip at 7:45 on how long should you be together before M

I would also get the book "I Promise You" by Dr. Harley, he wrote it for engaged couples.
Another good radio clip. Radio Clip Dr. Harley giving advice to engaged couples

Update:

Thank you all for your advice & concerns; both positive & negative.

My fiance & I have had many serious discussions since the incident. There has been no contact with the scumbag player that I have been able to detect.

She was reminded during subsequent serious discussions that she had a way out & that we could part ways & that I do not want her to feel trapped or unhappy. She has told me that she is in love with me & wants to grow old with me. She talked about her history of leaving relationships, that no one ever loved her the way that I do, her being with the wrong men, & that no one before me ever fought to be with her before & that she deeply loves me. She apologized & feels sorry for what happened & has promised more than once to never put us in this situation ever again.

I still monitor her phone, emails, & Facebook whenever I can sneakily do so. So far, so good. She even gave me a copy of her work schedule since because of the time of year she has to be at ceremonies & other events that run late or are on a couple of Saturdays (all verifiable info if I check) She knows that if she ever betrays me & I find out about it that I will go "no contact", forever. It will be as though I have been erased from her life. If I am betrayed, I will manage this feat with genuine fervor. I am rather adept at the no contact thing.

With that said, we have finalized wedding plans & will be married in July. Invitations have gone out & the majority of the planning is in place.

If you have to do all of this before you're married, then that is a serious red flag and a sad testament to your own self worth. There's millions of women out there. for some reason you feel you need to "work" on this with someone you haven't exchanged vows with.

Good luck. I hope she does indeed change. I predict you'll be back here in a few years telling us how she has an OM.

In all actuality, the continued snooping is a result of some PTSD that came back as a result in the breach of trust.

If she & I were to split up & months or years from now I began to see someone else, I would probably snoop on that person too.

After all of the articles, headlines & posts on this forum, I am convinced that our society lacks morals & ethics & that the majority absolutely cannot be trusted.