Relationships

Why would my friends with benefits tease me relentlessly about other guys?

My sorta FWB/ex (we never labeled it anything) teases me constantly about my guy friend and anyone who seems into me. He swears he's not jealous. He even insisted in the past that he's polyamorous and embraces the idea of me having other partners. He also said in the past that the idea of me being sexual with other guys turns him on. But why tease me relentlessly? Ex- I told him I was going to bed last night. He saw me back online 20 min later and he said,'I thought you were sleeping? Oh, I know, you're sexting with your friend." I said,"What is it with you and my friend?" He wrote,"All I know is last meetup, you AND him were BOTH late. Everyone was asking about you too." I said,"But, but... he was much later than me. I even went home with you afterward. So there :p" He ignored this and my goodnight text and resumed teasing the next day with, "Maybe you got it on with him before the meetup :p". So I wrote, "Do you WANT me to bang him? Would it get you off?" He said, "Hm sure if that's what you are doing, I want you to have fun. Bang away" He also teases me about guys that I'm pretty sure he knows I'm not attracted to. I don't think he's into me romantically anymore, but does it sound like he's being passive aggressively jealous? (I get that even casual partners can get jealous without feelings) Or is he just trying to be funny? Maybe someone can shed some light?
Why would my friends with benefits tease me relentlessly about other guys?
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