Marital bliss-Does it make a difference in stuttering recovery?

Tonight I spent the evening with my parents and brother and sister n law. My father stuttered severely as a child and up until age 40 or so. I was talking to my father as my mother was involved in an intense conversation with my sister n law. I was talking to my father about a stuttering issue as I can only talk to another person who stutters. He all of a sudden inquired of my mother if his stuttering bothered her when they were dating ( he was 16, she was 14). She hesitated for a moment and said she didn't really remember. She then stated that it might of but she probably liked the fact that he let her talk. My mom is a talker. My dad become a talker in the last 15 years or so. She stated she was so happy for him that he could say what he wanted now. I was thinking that my dad never received fluency therapy. He never talked about stuttering when he was young nor did his family. His parents were immigrants. He is a pharmacist and stuttering did not impact his career or family decisions. Why not? What makes him different than others? I welcome others feedback as to why some are so affected by stuttering and others not. BTW-My parents are married over 49 years.