Hey guys.
My son's first birthday is Thursday, two days from now. We're having a little party at our house that evening. We've invited my best friend and my husband's immediate family -- His parents, bro and SIL, and his sister and her two teen daughters, ages 13 and 16. Very small affair. My husband's sister just texted him asking if the 16y.o. can bring her boyfriend. He and the niece have been dating for about a year and I've only met him once in passing.
It feels awkward to have a virtual stranger at my baby's first birthday party, forever immortalized in the pictures. Also, I think it's a bit rude of my SIL to invite someone else to our house, especially on short notice (TBH, there will be plenty of food so I can't claim a problem there).
I kind of feel weird about this and want to say no, but I don't know if I'm justified in feeling that way and how we would go about wording that in the reply text so as to not upset anyone. My husband is annoyed she would even ask. We need to reply to her soon -- Thoughts on what to say?