My girlfriend, who is 26, is displaying some concerning behavior.

I’m in need of some serious relationship advice. My girlfriend [26F] and I [29M] have been together for a little over a year, and generally, things have been going well aside from some minor disagreements that are common in any relationship. However, early on, we had a significant argument regarding her past relationships. There was a particular guy we’ll call John, whom she was seeing casually around the same time we started dating. She was messaging both of us simultaneously and involved with both of us without either of us knowing. I’ve moved past that since we weren’t officially together at the time—we had just been talking for a month or two. Now, there’s a situation that has me concerned. She’s planning to visit her family next month, and I discovered she’s been messaging a guy she dated for a couple of months about three years ago. Their conversation seemed innocent enough—just catching up and talking about life. What worries me is that she suggested they meet up while she’s in town. I feel secure in our relationship, but given the history, I can’t help but feel uneasy. Additionally, I noticed that after I first saw their messages, they mysteriously moved into her deleted messages. We have an open phone policy, so I wasn’t snooping, but that behavior caught my attention. She hasn’t mentioned any plans to see this guy, which makes it even more troubling that she would propose meeting up without discussing it with me first. I'm torn about how to approach this. I don’t want to come off as petty or overprotective, especially if it’s not as serious as I’m imagining. But I can’t shake the feeling that something isn’t quite right. I could use some guidance on how to deal with this situation. No one wants to experience betrayal, and it feels like I might be heading in that direction. What should I do?