[20F] im not sure whether to trust my [21M] bf or not

So I \[20F\] have been with my boyfriend \[21M\] for almost half a year now, things are great and hes proven super good to me so far, he never lies from what ive witnessed and he is good to me…but recently he was being kinda weird when i was going through his phone (i do it randomly and he never cares when i do) and i was just reading his notifications until i read a girls name in a notification on his facebook saying “has accepted your friend request” now i dont try to freak out because in every relationship ive been in i have been cheated on and always ignored the small signs in hopes im just overthinking, and i asked him that moment who she was and why did he request to follow her but he just played it off as nothing i should worry abt and then took the phone away from me before i could even unlock it. I repeatedly asked him whats up with that and why is he being weird abt his phone and not letting me look through it and he started to get upset with ME for not wanting to let go of the situation. I left his house and drove out to kinda cool off and check his fb only to find out his account was hidden from me or blocked, not even part of my friends list, i came back to try and talk things out because i didn’t want us to end off in a bad note and told him how i felt about his reaction and the situation, but all he kept repeating was “youre an idiot” and “its nothing bad don’t worry abt it” but not a single direct answer that actually answered my question so i decided to leave it like that and to simply trust him.

Today i woke up from his bed and hes still sleeping, I checked his phone to check out what ive been driving myself mad about and sure enough she was on his friends list, I was blocked on messenger for a time period and his relationship status had been changed from public “in a relationship” to a private “single”. Now i dont know how to feel bc we work same shift together and i feel cheated on without any actual proof, he is sweet to me but i have bad trust issues bc of my past relationships, im not sure what to do especially because i’ve invested so much time and money with him and i dont want to feel a constant anxiety that he might be cheating in some way shape or form. And when I try to open up a conversation about it he ends up upset and saying things like “if you cant (this or that) then maybe you shouldn’t be in a relationship” and im not sure if hes right or not bc this is the first relationship ive got into after a 2 year no dating policy of mine.

I dont wanna end things with him over something stupid but i also dont want it to turn into small signs that i ignore and then feel stupid if my concerns end up happening.