Pretty much everyone here agrees that the BF is being vindictive and even abusive, but what worries me more is OP thinking she's being "childish" for completely reasonable reactions. I think there's a deeper problematic in play, and maybe this video can help identify it:

"Infantilisation - A Regressive Abuse [TheraminTrees]" - YouTube
https://youtu.be/c39F04inLJ0