Why would my “ fwb” get mad and block me because I’ve decided to see somebody?

I technically really wouldn’t even call him my “ fwb” . because this has been going on since 2018. and it kind of got deeper then sex , to the point we started saying we love each other , hanging out during the day, having dinner together. but we NEVER went farther or established things. so when I stopped talking to him because I felt like my feelings were being played with , I met somebody else and started hitting it off. so I posted him on my story and he slid up saying “ this is what you’re doing now?” . and I straight up said “ I’m confused , was I supposed to wait forever “ he replied “ u right.” Then blocked me. Now I’m having mixed emotions, that I thought were gone long ago. and I mainly don’t understand why he’s acting like a 🍆 head.
Why would my “ fwb” get mad and block me because I’ve decided to see somebody?
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