should i be mad or?

my boyfriend looked through my phone. "i don't look through your phone all the time" he said. so im assuming it's been more than once. im not really upset im just confused on why he had to do that because i never gave him a reason to. i asked him why he was so insecure and he said he wasn't. we don't do things like this. on top of that, he always claims he doesn't know my password, even tho i tell him a million times what it is, he obviously knows. i never in our 3 years that we've been together looked through his. now i feel like im obligated to. 😒 but i don't want to. that's just looking for trouble and i can't even get mad if i see something i don't like right?