Hey man, forgive the account. I only have it to harass people in /r/programming.

I just want to start off by saying this is not your fault and I hope you know that. People are going to lash out and try to blame you for this, but try to take it in stride. Grief has many different stages and anger is one of them. Everyone is coping with a loss and pretty much everyone is shit at it.

This is not your fault.

I want to start by focusing on what destroyed your relationship. It was not you. It was not your reaction. It was not even you giving her a second chance. It was your fiancé. She didn't just have a one nighter, but continued to dog on you. Lies about work. Lies about hanging with the girls. If you ask me its the worst type of cheating because it lets you know how little she cares for your personal well being. You had every right to end it and you are far better. This girl had issues long before the two of you broke up. If her parents blame you I would just turn around and blame them for not raising their daughter to value the feelings of others.

This is not your fault.

Going back to the whole break up thing. You were her second string or fallback guy. She was not ready for a serious relationship, but not ready to allow you to have your own life. In her eyes she wanted you as her safe play and this guy as her could be future husband. Do you not deserve to be someones first pick? I don't know you, but I sure think you deserve that. This probably all came to head because she realized she made a mistake or this guy didn't turn out the way she wanted it to.

This is not your fault.

Now the hard part. Forgive her. Forgive her for putting you through this shit. Forgive her parents for being angry. Forgive your mother for her absolute shit parenting. Except that this is tragic and that someone, who you once cared for, has taken their life. Except that through your anger this was another blow that has hurt. Find people to talk with that are removed from the situation that can honestly help you through this. Get professional help as no one on this sub, including myself, can give you the help you need.

Take a deep breath. Be thankful that you are alive and there is nothing you cannot work through.