My bf and his lies

Ok ladies so today I was talking with my bf a normal chat he told me he took longer to come today because he had gone by himself yesterday I laughed and playfully said “who did u think about” while laughing and he didn’t answer I asked again and he got very defensive and started yelling at me saying why I have to start with my shit right now and I said but I’m just joking and he said “wow you swear idc believe what you want” and I said ok and he said you of course! And I said “ok you swear” and he got super angry and yelled at me and then took me back home and left didn’t even get off or anything he told me to get off and I didn’t see him anymore. My problem here is why would he got so angry? I was just playing around I wasn’t even yelling at him! Is he hiding the truth?