Why does my boyfriend talk about breaking up and when I confront him he backs off?

[im a bad BH]

One time we were fighting for a few days so I ignored him, so he started calling me but because I didnt answer he texted "If you dont call me or txt me in 5 min we break up" So I texted after 10min and told him "lets break up then why wait 5 minutes lets do it now!!" and he immediately backed off and started saying he just wanted me to talk to him, even though I kept saying lets break it he didnt. Another day, he was saying that we've been dating for sometime, and I told him it wasnt that much, and he said that If I were be sad if we break up, and I said no I wouldnt be sad it would be nothing to me and he changed the convo. Also, we are different basketball fans so we were discussing about our teams and he joked and said I dont know if we can date having diff teams.. and I said "yeah you cant date me you cant date winners!" and he was like "im teasing!!" like for real.. why doesnt he break it up at once!!!??? if he knows I wont be sad, Im ready for it and I can handle it..
I've tried to do it... but he changes everything... It annoys me now.