This is too chaotic to read, it says more about the state of your mind than the content you tried to express with this word salad. Don’t let the anxiety spiral, it’s not worth it. Let’s assess if damage was done :
It’s very simple : did you or did you not respect the sexual and emotional exclusivity with your boyfriend from the date you discussed being exclusive? Outside of this you are free to have conversations with anyone, just let your boyfriend know emotional stuff before anyone else. Also if people you had sex before are still in your life somehow, he should learn this from you and the sooner the better.
Relationships are diverse but the one thing that transcend any diversity is : you should feel like a team with your partner. Do anything to cultivate trust and if trust was broken you can only wait to see if he can overcome the issue and trust you anyway. Sometime it’s gone forever and you can only learn how to behave better in the future : no blurred lines in regard to sexual and emotional intimacy. You don’t only want to be factually exclusive but also to avoid appearance of infidelity whenever possible.
No consensus about the question but if i had a FWB, the sex with the FWB would stop when date number two is planned : keep things calm in my own head if it works, go back to FWB if it doesn’t.
Well, they can only loose my vote once and it already happened a looooooonnnnng ago!