Should i be worried?

My boyfriend and I were wathing TV last night and he was texting constantly so, like i always do i took his phone and plugged it into the charger across the room so we could watch TV in peace. He yelled at me and started calling me another girls name then stopped half way through and corrected himself by saying babe. That didn't really upset me because i knew it was an accident. What upsetted me was the fact that he then unplugged his phone and continued to text. He was texting the girl he "mistook" me for. Then today he showed me the conversation between them and she was talking to him about how she wanted to start being FWB with certain guys. He then proceeded to tell me that he used to have a crush on her but they both agreed it would never happen so they just became really good friends. I'm really upset and was just looking for others opinions on the matter and maybe (actually much needed) advice on what to do.