It's called a private life for a reason.
When you do the job you do, you can't bring your work home and vice versa. It's not because you are ashamed of what you do or who you are, but purely because it is a choice, one that is made with everyone in mind. When someone who you work with finds out something about your personal life and broadcasts it, you just want to give them a telling off. Saying something along the lines of: 'I don't bring my personal life to work, so I don't expect you to bring it here for me! Understand??' You want to say it, you really do, but you can't bring yourself to do it. In the end you take it on the chin and make a joke, laughing it off.
However, the gap between the two worlds has been made smaller, by some idiot who thought it was funny. Some people may think you're overreacting, but it's called a private life for a reason. You didn't go and broadcast anything about him, why? Because you don't make it your mission to find out about his personal life, when you leave work you forget about him, or at least you did until he stuck his oar in where it didn't belong.
Maybe next time anyone will think twice, because you know if this happens again you won't be able to control what you say. You made it clear at the beginning that you don't bring your personal life to work, you don't date your collegues, you're not doing this job to make friends or to find a wife because you already have that.
You're friendly, you're a good laugh and you get on well with all (most) of your collegues and have a great time doing the job you love to do. But there's a line between personal and professional and you'll never cross it. You have heard of things going 'pear shaped' in the field because personal has crossed with professional, you can't let that happen, you WON'T let it happen.