<human>: Provide a brief overview of the text.

My Fiance and I have been together for 4 years, we have a beautiful 1YR old daughter together.  We have everything that we could ever want- nice house, great jobs, beautiful child.  We travel often and try to keep things fresh and exciting.  

When we first began dating, she was in an on-again, off-again relationship with another guy, who she had this type of relationship with for years.  It was actually the cause of her previous relationship to end.  

Before having a daughter, I made it clear that the relationship made me uncomfortable and insecure- When she had begun conversing with this guy again, in a very longing, and sexual way-- it nearly ended the relationship. 

When I confronted her on it, she broke down saying that she had a tendency to self-destruct when things seemed great in her life.  We were able to move beyond it, and she promised that the relationship with this guy was over and that it was something I would never have to worry about again.  

FF to now, and when everything seems to be perfect, I have been made aware that she is once again reaching out to this guy again in a way that is more than friendly.  

I haven't confronted her on it yet because I know this time everything is on the line--our seemingly perfect life.  But that rush of insecurity has come back, and I just wanted to turn for help here before making my move...
<bot>: Fiance [28F] has begun to stray and rekindle an old relationship with a guy she knows I have always been uncomfortable with... Relationship seems perfect-- looking for insight and advice.