I work in a very open-minded and sincere environment, but the other day my boss made a mocking remark about a personal situation with my girlfriend in front of everyone. I was completely taken aback and didn’t really understand it, but everyone laughed. Nobody said anything to him, and I stayed silent. Should I have reacted at that moment, or should I bring it up later? What would you do in a situation like this?
What kind of environment is this? The boss comes to your table and is chatting about personal life, and you’re just frozen. No offense, but if you didn’t say anything at that moment, everyone will perceive it as normal. It’s just not cool 
Is your boss always like this? Has he/she made comments about personal issues before? Or is there an extra level of intimacy between you two?
@sorgulayan had previously made remarks in a joking manner, but it wasn’t about such a personal topic. I think they misunderstood the closeness between us.
@atismaci you’ve found fault with the boss, but I think the employees who accept the environment like this are also to blame. You say it’s an open environment, but you’ve not established any boundaries. As long as you don’t react, this situation will become normalized 
Such issues can actually be considered as covert mobbing in the workplace. From an employment law perspective, the intrusion into your private life in a mocking manner is disturbing. However, if you are considering making a direct complaint right now, first talk to an HR representative or clarify the situation in a way that creates written evidence.
Go directly to the boss and tell them that you don’t want your private life to be discussed. It will continue like this unless you speak up clearly.
I don’t know, but could your boss have a personal interest in you? Because normally no one makes jokes about their employee’s partner. I think you should be a bit careful 
Daughter, you shouldn’t be so open about your private life at work. Just because you’re friendly doesn’t mean everyone needs to know everything. These kinds of things start with setting boundaries. If she were my daughter, I would tell her to talk about this situation immediately.
We don’t know what you said about your partner, but if people were laughing, you either shared something really silly or you actually gave the boss material. But be careful, this is serious