Why is he coming if I didn't invite him to dinner?

A couple of friends wanted to know when I’d like to go out for dinner to belatedly celebrate my birthday, so I invited three friends for this Thursday. No, I didn’t say they could or couldn’t invite anyone else, which in retrospect, I probably should have done.

One friend has invited her new boyfriend along, whom I have never met. I don’t want him at this “Girls’ Night Out” birthday dinner. She didn’t ask me if he could come, she merely emailed me Sunday night that she was bringing him. My other friend who has an SO asked me first if she could bring her fella, and I said no. She understood why and it’s not an issue.

When I suggested to my other friend that it would be better if her new beau joined us at an outdoor concert a lot of us are attending on Friday, she replied that he doesn’t like outdoor events, really, and she would rather him come to dinner with us. I feel like he’s being shoehorned into an event that was meant for me. I understand that I could be totally wrong.

Should I let it go and have him along?

Should I tell her, at the risk of offending her, that I meant for this to be a GNO?

If I do tell her the latter, how would I phrase it so that she understands that it doesn’t mean I don’t want to meet him ever, just not on Thursday?