Am I just insecure or should I be concerned?

So, my parents are gone for the week which means my bf gets to stay over! Last night we hung out with my sister and it was great! But literally every other second he kept mentioning her and kept repeating “you know you can tell her to come up” or “don’t forget you can invite your sister” like why are you so concerned with her?

I love my sister and we’re extremely close and I have nooo issue with her but every time she’s around, I’m non existent to my bf. Plus they seem to have more in common and vibe well together but I’d rather him just leave me rather then me having to feel this way.

What do y’all think?