<human>: Give me the gist of the text in a nutshell

My boyfriend and I have been together for a year, and while I had some insecurities in the beginning of the relationship, they seemed to have disappeared. (For a little bit of context, my parents divorced when my dad cheated, and I've also been cheated on in the past, so it's difficult for me to feel trusting of partners. I haven't really expressed these fears to my boyfriend much.) For the most part though, things have been really great between us.

Unfortunately, I've started to get a little worried recently and I can't tell if it's just me overthinking things. My boyfriend had never had a password on his phone, but a few weeks ago he added one, and I commented on it one day when I noticed and asked him why he'd put one on, just out of curiosity. He told me the code but didn't explain why he'd added it in the first place. I've also noticed that, while he used to leave his phone lying around, it's now constantly attached to him. Like, he has it with him nearly 24/7 whenever we're together. I honestly don't ever feel the need to snoop through his stuff or anything like that, I think doing so would make my feelings worse, but it's starting to bother me and make me suspicious that his behaviour has changed.

Deep down, I know that the solution to this problem is "talk to him about it." The issue is that I have a bad habit of second-guessing myself, and I don't know whether this is an actual issue *to* discuss or just my mind getting carried away with itself. I also don't know how I'd broach the subject without feeling like I was blowing it out of proportion.

Ultimately, I need an outside perspective and some friendly advice, and I'm hoping someone here can help me out.
<bot>: my boyfriend's phone habits have changed overnight and it's bothering me, but I don't know whether I'm being crazy and reading too much into it. Need a third person view of things.