Why does it bother me?

It’s been on my mind for years since my bf has had multiple jobs. Am I the only one that gets annoyed when he gives his Instagram to his female coworkers who are his age and post suggestive things? I just don’t understand why in a workplace does Instagram and usernames need to come up. I believe in a friendly coworker relationship, but that it should honestly only stay at work. I had a job before and a fellow male coworker would follow me and my bf had a problem with it bc it wasn’t “professional” so I just declined them or blocked them. Why do I get jealous just like he does. It’s not a toxic thing, we just agreed that we don’t enjoy the opposite genders on each other profiles to avoid drama and what not.