Well, he doesn't want to take the risk. And there's nothing wrong with that. You view his wanting to use condoms as not trusting you, but it's not about you. He's doing everything he can as well to make sure that no accidents happen.
And again, that's okay.
It's actually refreshing to see somebody who is always being responsible. You should respect that not look for reasons why it's a problem. You say he's just your boyfriend, technically you all should be doing as much as you can to be as safe as possible right now. And it sounds like you are. Congrats.
It's not just a trust thing, it's a personal comfort thing (for him) and removing as much of the risk as possible.