Would you go with the flow or ask for what you wanted ?

[Sparetoes]

DS1 is 23 next week. As it happens both he and I are off work on the day so I suggested we go it for lunch. My thinking (although I didn't say it) was it would be lovely to have him to myself for a bit and he could then go and do whatever with his GF in the evening.

He has assumed I meant for GF to come too. I don't think there's any grabbiness or anything like that (although I imagine he's also expecting I'll pay), he just assume the invitation included her.

I like her, they're good together, I'm quite happy to have a meal with her and often do, just on this occasion that's not what I intended.

I think he'd get it if I explained to him, but in her shoes I might be a bit put out to be uninvited - he's already told her we're all going out.

Should I have included her anyway?

WWYD?

Ahh, now he’s mentioned it I’d have to go with the flow.
The time to say something was when you first asked, then you could have said you were looking forward to just some mum & son time.

If he's invited her I would go along with it as it would seem unfriendly to uninvite her plus he clearly wants her there if he made the assumption.

It’s his birthday, let him do what he wants.
Excluding the girlfriend is honestly a bit strange.

It wasn't done to exclude her. More to prevent them from feeling they needed to include me in whatever they have planned for the evening. I'd assumed she'd be working and thought if he got seeing me out of the way during the day that would suit them.