My parents were married nearly 45 years before she passed away. As I'm helping my dad with his history, he glosses over tough areas (whether intentionally or he really can't remember, I don't know) and highlights his love for my mother. I know there were hard times - some I witnessed, and some my mom told me about later. I remember going to my bedroom at night after there had been some negative feelings and pressing my ear to their door in an attempt to see if their murmured voices were having an argument. I couldn't ever tell. They never fought in front of us.
No relationship is without its ups and downs, but I'm glad they stuck it out together. Still in love is an inspiration.
Happy Valentine's Day, you sweethearts.