Friend annoyed with me over NYE plans

Frankly I'm with you friends, you are appalling!
They raised the subject, you ignored/ghosted them.

This was unkind, borderline cruel. When they mentioned it and you said nothing they understandably would have assumed it was all happening as usual.

Frankly I think you’ve been downright mean and thoughtless , and I suspect you know it. The fact you were too cowardly to broach it suggests you felt awkward - so you left them with zero time to plan any viable alternative whilst you had fun with your new friends. I hope your new friends do the same to you at the last minute and you realise how hurtful you’ve been. Loyal and long term friends are precious- they didn’t deserve your lack of consideration.

You’re entitled to spend it as you like; but unless they’ve done something or you’re naturally drifting as friends/not as close, it was a bit of a shitty way of going about things;
But I guess you realised that at the time by ‘not saying anything’ when they made a suggestion about the tradition and now you’re feeling awkward.

not the best way to treat your friends, better to be upfront and say you’ve got other plans,

You were really mean not to invite your friends, I hate that kind of siloing of friends if it means people will be left out. It’s very childish. You were exceptionally rude to leave them hanging knowing they were looking forward to the night and had mentioned it months prior.

You sound like terrible friends, they are well shot of you.

I don’t know why you kept that tradition going for so long. Of course it got stale. You should have however made your change of plans known so your ‘friends’ could have made other plans. It’s obvious you didn’t want to invite them to the new group party. All you had to do was tell them it would have been rude to invite others to someone else’s party.

Jeez what a nasty pair you are. You dumped your old friends for your new sparkly ones and didn't have the guts to tell them.

TBH you sound like a complete p**t! You’ve been seeing these ‘friends’ for years and always doing New Year, but when something better comes along you jump ship without even having the decency to tell them.
if these new friends were really that, you could have explained the situation and asked if they minded your old friends tagging along.
i wonder how you’ll feel next year if your new buddies drop you? It will serve you right if that happens.

Don’t think you handled this very well!

It's likely to be a bit hurtful to your friends if you stop doing the thing you always do with them because you'd rather do it with somebody else. Shocker.

It's likely to be very hurtful to your friends if you just don't give a proper answer to their attempt to make their usual plans with you, and you don't give them a proper answer or explanation. Shocker.

It's fine, you'll just need to carry on making new friends to replace the ones you piss off every few years.

Unkind, and how would you feel if the tables were turned?

Wow. Harsh OP.

You were rude. The poor couple were left in limbo as to whether you were doing something together or not and then they find out they were dumped! Not nice manners...

Surely, as a matter of common courtesy, you could have explained the situation to them in good time? They would have been disappointed but would have had time to get used to the idea and had the chance to make alternative plans. I think your behaviour was immature and you’ve probably lost good friends as a result. Such a shame.

Actually, I'm now thinking it's surely a reverse

That is an absolutely selfish and extremely rude behavior. I'd consider that friendship over, because they will not be interacting with you again.

I think one of the things it comes down to is how many years. You only say "several". If it's say 4 years and post-covid then it's probably borderline but if it's 10 year tradition and and you ended it with no notice then you're definitely being unreasonable. At the very least you should have told them and offered up an alternative night such as the Saturday either side.

Sounds like you weren’t very honest and they were left unsure and then ditched.

of course you can do what you want - but maybe told them earlier and clearer?

I think this is the issue. You should have told them you have other plans this year.

Having the ability to say "no" is a sign of a strong character and healthy boundaries.

I think you were really unreasonable and rude to just ignore the fact that they invited you. There’s nothing wrong with not wanting to spend NYE with them but the way you handled it has made it seem like you don’t care about their feelings at all.

As often happens, there should be an Etiquette forum, which is the issue here.

There are two crucial things that are not totally clear in your post - whether in each case it's a foursome, and whether you provided advance notice.

Assuming these would both have been foursomes, you should have either:
1)Told your old friends very early, a month in advance, very apologetically that you had other plans this year.
2)Told your new friends that you would have loved to, but at this late date, you have a traditional get-together commitment with others, so perhaps you can re-think this next year.

However, the third possibility doesn't seem to have occurred to you:
3)Host NYE yourself and invite BOTH couples.

Op no one is forcing you but how would you have felt if it was the other way around? People are flaky and drop people like hot bricks you should have had the decency to tell them you have basically shit on them. If you were my friend I would be fuming especially as you didn’t tell them. You’re a shitty friend tbh.

Shoddy behaviour. You didn’t want to invite them or celebrate NYE with them and want others to make you feel less crappy. Not clear why they couldn’t be invited too - your responses on this are feeble. YABU.

Why not though, how do you think people meet new people. You should have invited them along