To be upset by PILS choice of celebration meal.

Exactly! I don’t eat lamb or steak. I just asked my DP if I was a fussy eater and he’s still laughing

shellfish, anchovies, sushi, pink burgers, pickles, spicy food, I eat most stuff but I can’t touch lamb and I dislike steak

I don't think you're a fussy eater.
However, I highly doubt that the restaurant would have made you sit downstairs and if you didn't speak up, how would you know this. It's a shame your pils didn't think of your requirements, however, you're an adult and can make reasonable decisions.

That starter and main would be my idea if hell. Did they notice you didn’t eat? What did your husband say?
What u should have done is asked the restaurant to take the plate away and just bring vegetables and potatoes with no meat juices. It astounds me that people invite people to THEIR party and then treat them like shit and don’t think about their needs. It really would not have been hard for them to say you were vegetarian . I would never have guests and give them something they don’t like. All those people saying you are entitled and fussy just ignore that. You have every right to be annoyed. Your husband should also be cross that you were treated like this.

Could you not have just eaten whatever came with the lamb? Presumably there were vegetables or something. You could have said that you were allergic to salmon, though I understand that if you were expecting a main course you could eat you might have thought it wasn’t worth it and then the moment would have passed. I’m sure they could have brought you a bread role to fill you up a bit at least. You should have spoken up. Pretty poor of them to forget your salmon allergy though.

I think pre-deciding the entire menu for 20 people is bonkers. Yes, it's their celebration but why wouldn't you want people to eat food they enjoy. They could still have had salmon and lamb if that's what they liked.

How is she a fussy eater?

She has an allergy to one thing (pils we’re incredibly out of order, not to mention dangerous, not flagging this to the restaurant if they had pre ordered meals especially as they will have been asked if there were any allergies to be aware of).

So the only thing she doesn’t like is lamb. Do you literally like every food in the world? Is there not ONE thing you don’t eat?

Oh and I'm sorry, OP, that this has gone a bit "cancel the cheque", with people repeating that you should have asked for something else when your update clearly states that you did ask and the restaurant wouldn't accommodate ...

Of course hubby thinks its rude for you to leave the party to eat but not rude of his parents to be so thoughtless there's no dinner for you to eat. These are your inlaws. If they forgot to think of you as their dil and they are decent ppl they would be mortified (as hosts )that you had no dinner and would not think its rude if you was hungry to go down and eat something.

So your PiLs know that you're allergic to salmon and can't stand lamb but they ordered a set meal of salmon and lamb? They sound horrible to me and I'd find it hard to forget this.

I would have ordered myself something else from the restaurant menu as soon as I realised I couldn’t eat the preordered dinner.

Wow that’s a bit of a stretch. The OP has already explained why she couldn’t order an alternative on the fly. At least read all the OP’s comments before jumping to such ridiculous conclusions

My inlaws did something similar with me and they ignored my repeated (polite) comments way before the event, that I didn't eat meat and could I please have an alternative.

At the meal, I politely and quietly asked the waitress if I could have a vegetarian option or just the actual vegetables without the meat and they accommodated me.

It's very rude and inconsiderate of them if they knew about your reasons for not wanting salmon and lamb, but if they're like my inlaws, then they think they know best and don't give a damn so long as they get their own way.

I am pescetarian and have coealics. I always do my best to make it easy on people hosting or at parties etc. - offering to take food with me, checking with them or the restaurant for options etc.

But it does always make me a bit sad on the occasions when I have been considered at all by the hosts, so I understand how you feel. And it's not fun seeing everyone else enjoying a meal while you just sit there and then have to eat a pack of snacks in the car on the way home.

And it's happened to me before where restaurant wouldn't serve me something from the restaurant menu instead of the set menu if it hadn't been booked in advance.

How’s your relationship with them otherwise?

I’d think they were careless and not the greatest hosts, but if it’s the only incident I’d let it go.

I don’t understand - surely when the salmon arrived you said I’m allergic to salmon please take the plate away … and the restaurant did not say I’ll bring you something else? Or did you just sit there with salmon in front of you and not say anything?

I don't have any food allergies but my child does. I call restaurants myself to discuss the food even if the host has already done so just so I am double sure everything is going to be ok. I would recommend going forward that you reach out to catering yourself.
With food allergies and intolerance being more common now I think it is hard for hosts so manage it all on top of party planning

You were in a restaurant. Why on earth wouldn't you ask the staff for an alternative? Even if you had to pay for it yourself it doesn't make any sense to sit there eating nothing. Are you a survivor of some kind of horrendous abusive childhood that taught you to have zero self-esteem and no capacity to advocate for yourself? I think you may need some counselling.

Not eating salmon due to an allergy and having one other meat you don't eat is not fussy. You cant count the salmon and most ppl have a few things they dont like to eat.

Not fussy means you are happy to eat what is put in front of you, so the fact you wont eat 2 really common things means you are fussy. Surely most people assume that if you are forming part of a big party like 20 the restaurant will as you to pre-order; whether its one choice for everyone, or a set menu. I think with your dietary requirements, and the fact that dealing with fussy eaters isn't normal in his family the onus is on you to check.

I think people who like and are willing to eat everything are few and far between.
Often when people accuse someone of being ‘fussy’ it’s because you don’t like something they like and can’t imagine why.
I also eat almost everything. I don’t like seafood and actually I’m not allergic but I am intolerant to it anyway. My PIL called me fussy for 20 years because I wouldn’t eat it. However I could have listed a thousand things they wouldn’t eat because they were foreign or strange or not cooked how they liked.

I think adults are not allowed to eat things they don’t like.

@Gall10 , there is no way OP could have eaten the main course without the meat. It was covered in lamb gravy. If you don't like lamb, the smell is enough to make you gag.

Well yes it is was really thoughtless of your PIL not to accommodate your dietary requirements and I would be a bit miffed too. However, if I had any kind of allergy, and such a strong dislike of something that it would put me off eating the sides, I would have at least double checked with my in-laws to that they hadn’t overlooked my requirements and/or spoken directly to the restaurant. This isn’t all on your in-laws.

@Shardlake63 I see where you are coming from but as someone who suffers from Coeliac Disease whenever we are invited somewhere i will always ask / check, look up the place and menu's etc. Perhaps they forgot or didnt think. What i will say is if its a sitdown meal and they chose for everyone then they should have had more thought. I can only speak for myself but i consider it my responsibility to make sure there is food i can eat so i ask the questions before the event to make sure.

Surely the waiter would have double-check any allergies before serving? Even if you had 'pre-ordered'. AND if you had to pre-order, why did everyone have the same? And what kind of establishment has a private dining room but doesn't use the kitchen? Or wouldn't let you eat from that kitchen in the private room? It all sounds v complicated. I've forgotten what your order was now.

It is awkward to speak up at a in-laws celebration though as you do not want to be that person. Where was your DH in all of this? Mine would have done something quietly. I can imagine another type of DH would have happily gobbled up the meal you left. So which type is yours? Somewhere in the middle hopefully.