My boyfriend uses protection when having sex with me, does this mean that he doesn't trust me?

Using protection every time is the responsible thing to do if you're not ready to have children, and it doesn't mean that he doesn't trust you. Of course, it's still possible that he doesn't trust you... but it's also possible that he doesn't trust himself - if he has engaged in risky behavior in the past or present, he may be protecting you from him.