For context, my bf and I (mid-late 20s, dating for a year) have a mutual circle of friends consisting of people who went to high school together (excluding me and another guy's girlfriend).

We've been hanging out as a group for about 6 months, usually going bout to drink or having small house parties and the girl, let's call her Marie, is trying to get close to my bf. Like she would try to talk to him for hours while I hang out with the other girls, she would take party photos only of my bf and even selfies with just the two of them.

Now I know I shouldn't have done this but the other day I went through his laptop to read their messages and while he replies in a very friendly but concise manner, she does most of the talking and initiating conversations. Instead of asking in the group chat, she would only message him directly asking if he's coming. No mention of me. And after the most recent day out she only messaged him how he's feeling and if he got good sleep.

I feel like she's definitely crossing a line here and my female friend agrees, but I'm not sure what's the best way to tackle this.

How do I talk to my boyfriend without sounding like I'm crazy or overly jealous.