why do i feel hurt

okay so i know this is considered toxic. But i have trust issues and have been cheated on before but i went through my new bfs phone and saw texts about me as well as another girl. While we liked each other he was calling another girl hot. He said this to his friend and i just felt hurt reading that. What do i do to deal with this because we weren’t even dating but it’s bugging me a lot now. Would you think he is unloyal or am i overthinking, cause i know i got insecurities.