Hi iamquaker, welcome to Psych Central.

A person can experience flashbacks even YEARS after experiencing traumas. I experienced flashbacks from my childhood in my fifties. It frightened me that I could even experience flashbacks going way back like that.

It is very probable you are suffering from ptsd. Are you working with a trauma therapist that specializes in PTSD? A person can want to experience a normal relationship as you describe but struggle with flashbacks, including emotional crippling ones when they try. These triggers are "intrusive", no one chooses to experience them.