Well as a guy I can see where that might have caused him some concern, especially if he has any self esteem issues. I could see it as a guy that dated a girl 24 years ago, she left me, got engaged, now 24 years later she is back in my life, I am excited to have her back, then he see's the pic's on FB and she is "pinning" for the guy she left me for.....I gotta say that would hurt, how much it hurts I guess is the question.
As a guy I think you need to be very honest with yourself in asking what you want from this "old boyfriend", then you need to very honestly, and directly let him know what you feel about the relationship, and what you want in the relationship.
Directness always worked best with me, it is one of the things I love most about my SO!
4 kids all adults.
Married 22+ years.
I have moved on and life is good!