NTA - first of all, sorry that you’ve gone through things in the past that have caused you to put a barrier up when it comes to trusting individuals or actually giving them your trust.

It’s not that you don’t trust your boyfriend... I’m sure you do, but now after him saying “no password sharing”, what ifs are definitely going to pop up in your head, which is understandable/okay. But these what-ifs/thoughts need to be talked about - mention why it’s causing you to feel this way, etc.

I’d suggest that the two of you talk, mentioning that you do trust him and never meant to insult him in anyway, however based on previous experiences your naturally used to putting up barriers towards other people when it comes to giving them your trust.