<human>: He is my ex-boyfriend but we have been having casual sex for over a year. 

He NEVER told me about this. I found out when I joined his Xbox party with his friend who he was telling. He had went to a party and made out with a girl, and almost hooked up with another one (apparently she was too slutty for him so he didn't). I snapped saying why didn't I know this?

I talked to him about it tonight and he said I am annoying. He said we are no longer dating so he can do whatever he wants and there is nothing I can do about it. However, if he made out with another girl, he could have sex with another girl if he hasn't already and just never told me! Maybe I'm paranoid but I feel I 100% have the right to know what he is doing. Things like STDs come to mind.

Should he be telling me or if it really none of my business? It also hurts me that he would tell his friends about this but hid it from me...

Can you provide a brief rundown of the text in within 3 sentences?
<bot>: FWB made out with a girl at a party, had no intentions of telling me until I found out by mistake. He said because we aren't dating what he does is none of my business.