Why does he talk about me to his friends?

I text this guy funny things, and I was acting like I was somebody else, basically I was pranking him. I was saying absurd things, and he told me he texted his friend the convo, but I know his friend so it's pretty awkward lol. He seems to text this guy I know everything I do! He took a video of me once and sent it to his friend, and his friend is married , so he's not trying to hook me up with his friend or anything, plus he's really jealous and I highly doubt that. But why does he seem to text his friend things that are associate with me?
Why does he talk about me to his friends?
Post Opinion