Why do guys randomly mention that they have a girlfriend?

[Stinemart22]

So there’s this guy from work I’ve always thought was attractive. Met him finally and mid convo he slipped in that he had a girlfriend. I didn’t ask but it somewhat fit into what we were speaking of but somewhat unnecessary. Why do guys do this? I was not fawning over him at all or showing my interest. Pretty casual convo with mostly work related stuff. Is it almost like a conscious reminder to himself or do guys say this when they’re cocky and think every girl is into them?

[SixFootSexy]

Girls do this way more than guys, in my experience. Even if you show the slightest bit of interest and they're not about it, "I have a boyfriend."

Now, sometimes they'll backtrack if they aren't really in love with their boyfriend. But that's another story. XD

[spartan55]

It's called drawing a boundary. Doesn't mean he thinks you are hot for him. Not sure why this would be such a big deal to you.

[Fireguy17]

He may not have been sure what your motive if any was, and wanted to let you know that he was in a relationship.