When I ended my fwb relationship

For awhile now, me and an ex of mine decided to make an fwb agreement (I know bad idea) until one of us found someone. So recently me and this guy, who I've been talking to for a few weeks, went on a few dates and ended up having sex (which was absolutely amazing). All I can think about after is how I'm going to end my agreement. Few days later, my fwb messages me asking if I wanted to have sex and I told him what happened and that we had to end it. This bitch has the nerve to say "did you think about me?" What I really wanted to say was "bitch I was thinking about how you were terrible in bed and that you have a really small dick" but I just ended up saying no. Honestly though, he was really bad in bed and I'm glad that's over with😂