<human>: Can you condense the text into a few key points?

When I was six, my father left my family in the middle of the night, taking most of the money and the only car. I had eventually learned that he was cheating on my mom with another woman. I even got to read the actual letters from the other woman that was sent to him. It's contents contained comments on sex, her knowing he had a family and her missing him etc... 

My mother decided to give him a second chance to work things out and be a family again. During this second chance is when he left. 

Ever since then, I never heard from him. Neither my siblings or I received so much as a simple birthday card even. No phone calls or letters, nothing. I have since been left wondering "Why?". Growing up, this has been gnawing at me for a great deal of time, wondering why he did the things he did. What was wrong with me for him to do such actions, if he had other kids and what not. Sometimes I get curious and Google whatever I could find on him. 

Which leads me to my current situation. I believe I have found the residence of him and his girlfriend(?)'s home. I would like to write him a letter asking why and also to vent what I feel towards him. I have spoken with my mother about this, but she feels I might end up being hurt from not getting the answers I am looking for from my father. I feel this could be true sadly as well. I also feel like if he ever told others about us, he might have painted my mother to be the villain who wouldn't let him see his children, which is entirely untrue. I guess I fear his denial as well :/  

Would this even be a good idea? Perhaps cathartic at the very least? Or would I just be hurting myself? I would really appreciate some advice on this or other people's experiences with contacting a parent that left them. What would be the best way to go about doing this if I do write?
<bot>: May have found out where my father, who abandoned me, lives. I am unsure if it's a good a idea to write a letter towards him venting my feelings and asking why.