Don't Want to use Voucher on 2nd Friend

I would tell her that you were looking forward to a catch up just the two of you. If you are up for a lunch for 3 then go but you don't need to. You could just say let's reschedule for the two of us another time so we can use that voucher.

Very cheeky of 1st friend to invite the other without checking with you

I agree that this would be the best approach. But might not go down well with your good friend.

The real problem here, though, is that your friend feels free to invite her other friend along to things without checking with you whether or not that is OK with you.

I really feel for you. I was in this dynamic for 20 years, where a good friend would want to invite (a similarly stingy, never invited me to anything in return, person) her good friend to most things we organised. Like your situation, she never got how I didn't really like this third wheel.

It is a really hard dynamic to break; and in my case only got broken when the stingy person moved to a different city and got stroppy with our mutual friend for wanting to arrange visits to her that included me.

Minor clarification and typos

"Sucking it up" is not an option. There's no point going out for a nice meal unless she's going to enjoy herself, and she won't if it means all three of them present and her being sidelined again.

The voucher's a bit of a red herring here. The real problem is that you don't enjoy get-togethers when the first and second friend are both present. So cancelling is the way to go.

You need to suck it up. Cancelling third friend could back fire and you could be the one left out in future .

I've been blunt with a friend in a similar situation (without the voucher though). She said she'd ask her other friend to join us and I just said, "I'll drop out then if she's coming. I've noticed she always cuts me out of the conversation so there's no point in my being there." My friend did say, "That's a bit blunt!" and I just shrugged and said, "It's the way it is." We now meet up on our own or with other friends regularly, but not with the other friend.

The issue as well is that you say when the three of you go out, you can be excluded. No way I’d spend my voucher on an evening like that anyway .

I think what you’ve suggested saying is perfect - the voucher won’t stretch to three so I won’t be using is.

One thing that really infuriates me is people inviting someone else to any social occasion, without first consulting the person who invited them. It is the height of rudeness.

I would either text Friend A and say that the voucher is only for 2 people so can she please uninvite B. OR just have a migraine or urgent appointment arise. And then re-book the meal, inviting another friend who doesn’t take the piss.

I don’t think the 3 rd friend would expect to use the voucher would they? Surely you just use it like you would cash at the end?

I think you need your big-girl pants on and you need to communicate how you actually feel with your friend.

You cannot use the voucher on just one friend. Keep the voucher to use another time.

"I'm sorry Kate but there's been a misunderstanding. I've nothing against Laura but I invited you as I really wanted to share a meal with you and catch up, and when it's you, me and Laura it's a very different experience and not the thing I was trying to set up. Obviously it's fine for you to go ahead and meet up with Laura that day if you want to but I won't join you. Please can we find another day where we can go as just the 2 of us?"

I wouldn’t pretend to forget the voucher as all meal you’ll be thinking about it and your friend may have planned her budget on relying on the voucher.

But I would just say…Is…. Coming ? If so we can’t use the voucher as it won’t stretch but if it’s just us two we can.

I wouldn’t put emotion into the message saying you wanted his you two but keep it y about the voucher

You probably need to come clean and say you just wanted the two of you and you wont be using the voucher for any hangers on that you didn't invite.

It's so rude to invite someone else witbout asking first, I have a pal like this and he invites ppl we dont even know to try snd see his mates at the same time, so we end up meeting randoms for a few hrs and chatting but never seeing them again. Annoying in our 20s, in our late 30s when time is a premium its infuriating!

I'd just message and say voucher won't stretch to three so to avoid singling her out I'll save it for another meeting of the two of us.

Forget the voucher.

Just don't mention the voucher and if she asks then say "oops I forgot it".

Is it at all possible she didn't realise you were planning to use the voucher to reduce the price of both your meals?
Because it's a present to you from a relative, maybe she thought you'd just use the voucher for yourself and had just mentioned it to her so she wouldn't be surprised when it came to paying.

Absolutely save the voucher but make sure you tell her clearly right away that you won't be using the voucher and everyone will pay for themselves.

If you feel like you can then next time you invite your friend somewhere, say to her please dont invite anyone else, I really want the two of us to have a catch up.

Save the voucher for another day.

Pretend to forget the voucher and use another day? Or just cancel.

Just don't mention the voucher and it probably won't be mentioned.

If it is (and there are 3 of you at the meal) just pretend you forgot to bring it.

The voucher is for 2 and it will run out soon if I don't use it?

She probably doesn't know how I feel deep down about the dynamic

Then you need to tell her. She is not a mind-reader.
Find your words.
There have been some good suggestions here, along the lines of "I wanted to just catch up with you one-to-one, so I will bow out on this occasion, lets meet another time".
No need to criticise the third party or say you don't like her.
No need to mention the voucher, as that is not the main issue.

Tell her that the voucher is a meal for 2, not 3 so if she’s now bringing X along it’s not going to work and you’ll need to rearrange for another time.