Why did he do this *10 EASY points*?

Okay, I had a FWB (We only made out, I didn't go any further) for a few months and we were only with each other. Then yesterday, he made out with these twins (Yup, at the same time...ew) and his friend Skylar told me he liked me. I like him too, and he asked me out and I said yes. My ex FWB saw us kissing and said "Hey now" jokingly and pointed at me. And he tried to get Skylar to come hear his rap that he made up, but Skylar said "I'm staying right here" (He was staying with me :) ) and my ex FWB kept hugging me really tightly and Skylar said "Oh now I'm jealous" I tried to get my ex FWB to stop, and he said "You don't love me anymore" Why was he doing that?