Am I Overreacting

I (20 y/o female) have been friends with my best friend (19 y/o female) since we were in 4th grade. I began dating someone (19 y/o male) who was a mutual friend of us both about two and half years ago. Seeing as though they were friends before we started dating I’ve never been concerned or bothered by the fact that they had a friendship and regularly communicated. For example, I know they text almost everyday and my bf at least has never been defensive or tried to hide it. I know I can trust both of them, and it’s not really my right to tell them to stop talking just because we’re dating now that’s just weird. However, recently I found out that she’s been inviting just him to her church for the entirety of this year. When he initially told me I thought nothing of it because it’s church and not like a club or bar, no concern. But it’s been a couple days and for some reason I’m a little confused by it. Me and my bf go to church together every Sunday so wouldn’t it be natural then that she just invites both of us to her church? Also, me and her have a closer relationship, so why would she not think to be inviting me to her church along with him? If it had been that she invited me one week and then maybe him another week I guess I wouldn’t be concerned, but it’s just odd to me that she only ever asks him if we’re best friends? For context, they’ve never actually hung out just themselves, this is the first time I’ve heard of at least that she’s making an effort to just be with him. When they do hangout or do stuff I’m always there because we’re all mutuals and she’s my best friend so it makes sense that me and her want to hangout as well. I don’t know, I’m not really upset by this because I don’t think her intentions are bad. However I can’t stop thinking about it and just want to know if I’m confused for no reason.