Did the fact that I was raised by an abusive stepfather and alcoholic mother cause me to cheat on my husband?

A lot of us were raised by messed up parents. You, however, aren't your parent. You're you, and you are responsible by every choice you make. You're blaming others for your bad choices. You have affairs because you have no self control, or you feel entitled to behave badly. It's not your parent's fault. You can't blame them, just like a child molester can't say it was his bad upbringing so he should be excused from prison. You are responsible. Not your parents.