TLDR: Idk if this is a bpd thing or if I’m just like this for some reason but any time I meet someone new I feel like I need to make myself very likeable and I need to impress them. 
Context: My boyfriend has a coworker that he talks about a lot that I’ve never met. They’re pretty close at work and have exchanged numbers and want to make plans to hang out. My boyfriend asked me if I would want to go with them to do something and I immediately got nervous and started thinking of what his coworker would think of me. I am comfortable in my relationship. I would never cheat on my boyfriend. But for some reason I feel the need to get validation from his coworker? Why do I care so much? I have never even spoke to the guy I just know his name, some funny stories about stuff at work, and saw one blurry pic of them messing around. It’s not like he’s MY coworker. I don’t understand why I have these feelings and it’s making me feel like an asshole.