My father had several “girlfriends” during his 17 year marriage to my mother. I even got the chance to meet a couple of them along the way, at least one showed up to his funeral. Dad always denied it but the evidence was pretty obvious.
Despite his “extracurricular activities” he was always home for major holidays like Thanksgiving and Christmas, even if his thoughts were elsewhere. As I’ve gotten older I had the opportunity to meet one of his girlfriends in 1999 just before his death in 2004. She was a 30, Dad was 60 then. She and I chatted for over 2 hours.
Amy was a sweet, beautiful and intelligent young woman who had recently graduated from nursing school. She and my father had been friends for 5 years since she was 25 when Dad was 55.
She confided that the most difficult part of a relationship like theirs was that she never got the chance to see him on holidays. I know Dad cared for her a great deal and from my conversation with her the feeling was mutual. I actually felt bad for her.
The “mistress” seems to always take a backseat to the guy’s “real” family. It means often being alone at times that were always intended to be joyous. Based on our conversation that was the worst part for her.