My (M27) girlfriend (F26) told me she might sleep with someone else if I were okay with it. Am I in the wrong for being upset? (context in description)

I'll have to give some context because it might not be as bad as I'm making it out in my mind. We've been together 7 years. The other day we were watching a show, and in the show, the girl asked the guy (they were partners) if he would sleep with someone if she were okay with it. The guy gave an answer that was basically "maybe, it would depend on the circumstances". The girl was upset.

Now back to my relationship. My girlfriend defended that guy's comment (out of the blue too, i didn't even comment on it). She was saying "I think that answer is fine. Obviously assuming that the partner is okay with it. If it were us, and you were okay with it, I'd probably say the same thing".

How do I take this? I'm a little sussed out. Because if the roles were reversed, even if I had permission, I wouldn't do it because I wouldn't want to sleep with anyone else. So it's not a "maybe", it's a clear no for me.

I'm pretty sure my girlfriend wouldn't cheat on me but I can't help but feel hurt by her statement. Even knowing that it was just a hypothetical statement and all that. Just the idea that 'oh if I had your permission I might start going around sleeping with other people'... Am I in the wrong for feeling this way?