My boyfriend compliments my friends alot?

[Shenna]

Okay, so my boyfriend doesn't know my friends in real life, because I was talking about my elementary school friends and introducing them to him.
So I tell him all this good stuff like, "Oh, they're really pretty, athletic, nice.." etc, and all of a sudden he stalks them on Facebook and says, "Yeah, they ARE really pretty."
And then he goes all like, "Oh, I'd love to meet them one day."
And I know it's kind of ridiculous to be all jealous and stuff, but there was one time where I remember it specifically making me nervous.

Like, so I asked him one day, "So would you ever cheat on me? And if you were, who would it be?"

And he replied, "Of course I wouldn't cheat on you! Except maybe for Amber or Karen. HAHAHA kidding!"

Like, I know he might be joking, but does it mean anything otherwise? I really want this relationship to last, however, he's giving me mixed signals. Does he like my friends and prefer my friends more than me? He compliments me alot btw, and he tells me that I'm cute/beautiful/amazing everyday. But he calls my friends pretty, too. And made that terrible joke.

Am I just overreacting/overthinking?

Thanks c: