help ladies:((( don’t trust him

so my bf and I have been together almost 3.5 years... towards the beginning of our relationship he was friends with this girl who would continuously tell him that I wasn’t good enough for him, that he should dump me etc.. although she has “never had feelings for him”. But like whatever and keep in mind she has a bf. So about a month ago I saw that he was recently messaging her and I’ve made it very CLEAR that I’m uncomfortable by them talking bc of how she’s tried to come in between us. well he partially lied about what they were talking about although I knew the whole story completely because I read it over and over. He held back a lot of details. I was so hurt and upset and he knew this. Well now a month and a half later I have this gut wrenching feeling that he’s talking to her behind my back AGAIN.. I don’t want to say he’s cheating and flirting with her bc idk??? but it’s the fact that I’ve asked him not too and he doesn’t respect my feelings and emotions enough to stop talking to her?? He knows I’d drop anyone in an instant if he was worried or upset by someone I was talking too...? I’m sorry if I sound psychotic.. but it hurts me ya know? he knows i struggle with trust issues but he goes and does this...?? what do you ladies think?😞