To not invite dad’s GF to my wedding?

Or rather than prioritising the DM’s feelings we can all be grown up about it and deal with it because it’s just one day.

I think what you have said here explains your mum's feelings & reaction.
Your insensitive father trying to force his gf on your siblings in this way - no wonder your mum feels like she is being replaced.

Does she live near them all to witness this in person?

And, let me guess, is Gloria much younger?
It surely doesn't take much to see why your mum is struggling with all this?
You are in control of your wedding so do what will make you feel most comfortable on the day and if you think inviting the gf will upset your mum & make you worry about her all day then just don't. You don't have to.

Why even consider inviting people you are not sure about?
I never understand this attitude; it is your wedding, you are paying, you do not have to invite anyone you don't want
If anyone challenges you, simply say 'i don't want them at my wedding'. No explanations required.
If you haven't met the gf, don't invite her. She can travel with your dad if he wants, but she'll have to amuse herself for the day
You've only just started planning. Get this addressed now before it becomes out of control

We don't even know that his current girlfriend had anything to do with the affair. From what the OP says, the affair was years ago and the current girlfriend wasn't involved and is innocent.

Those saying the mum should suck it up have clearly never witnessed the devastation felt by a woman whose husband of 30 years in unfaithful. It’s not something you get over quickly .

In most situations it might be "normal" but, as the OP says, this is not a typical situation and she knows it will cause tension on her special day.
Lots of people seem very cross that the OP's mum is still upset at the ending of her marriage and not coping so well but that's the reality of it.
Whether people think she "should be" over it all by now or not, the fact is that she clearly isn't so even if a relationship of a year is now officially a forever one or whatever your arbitrary rule is, inviting the father and his gf will create a difficult, messy situation which could be avoided by not inviting her.

If you don't want someone you have never met at the wedding that's completely valid. I'd speak to your father and explain you're happy to meet her over that period but she's not coming to the wedding itself. Both your parents should be thinking about you in this situation

@HelpAGirlOut1234 a year because it shows a level of commitment. It’s not about them breaking up or not. I think it’s pretty normal after a period of time to start inviting a new partner to family functions.

I am going to vote for not inviting her, you never met her, surely your father should be the one being less selfish and should know that bringing yet another woman in the mix on his daughter’s special day will bring more stress for all of you.

@Jumpers4goalposts why the arbitrary time frame of a year? It's not like after a year they're never going to break up? More relationships than not end after people have been together a year.

And 'the fact is' the OP does not know this woman, so why would she want her at her wedding? Her parents relationship ended less than 2 years ago, why would OP be happy with him bringing one of his girlfriends to her wedding and have him rubbing his relationships, and therefore past affairs, in OPs mothers face?

It’s what happened at my parents wedding with my grandparents and it worked. So not utter nonsense.

It seems as the OP has no particular issue with her DF’s girlfriend and I expect if the DM was not around she would be invited no issue. The fact is if longer than a year the girlfriend is a big part of the DF’s life, DM needs to accept it and move on herself.

Or maybe her father realises that this is his daughter's wedding and leaves the random GF behind for one day and doesn't make any of this an issue for OP and her fiancé? The OP has never met the GF, and is likely not to have any sort of relationship with her if she hasn't even seen her father in person in 18months. Why would she invite this random woman to her wedding? Particularly if it would upset the mother she says she loves a great deal?

I think it's completely unfair for your father to expect you to meet his gf for the first time, at your own wedding. He must know it's going to cause problems with your mum being there too. I think you need to talk to both of your parents and try to work out something that you can all agree on. Like maybe his gf comes to the reception, but not the ceremony?

Yes, because that would work, just keep them apart. What utter nonsense!

She won't be part of the OP's life, she never sees her dad which is why she hasn't met the gf yet.
And the OP is an adult, she doesn't need a step mum. It sounds like this woman will always just be her dad's gf who she never sees.

Why would you invite someone you don’t know just because there are your dad’s latest GF? I can’t imagine upsetting my mum by doing that. It’s one day, can’t your dad cope on his own for one day?

I’d invite dad to the day only (as she’s a fairly new partner at the moment) and she travel with him for the trip anyhow as it’s only 1-day for the actual wedding. Perhaps you could have dinner with them separately. Seems like their 2nd separation is more recent (2022 if I’ve read that right) so could still be a bit raw for your mum.

I think if you DF has been with new GF for a year or more invite her, it’s probably serious and she’ll be part of your life. Just tell DF to keep GF away from DM.

Have a talk with your father. He knows your mother is not ready for a girlfriend and he should be the grownup and not bring her to your wedding so as not to cause a scene.

Honestly it’s completely irrelevant if anyone on here thinks your mum should put up with it for the day. The fact is she won’t. On top of the emotion of a daughter marrying she inevitably won’t handle it well. Even if she tries her hardest for your sake, you’re still going to spend the day watching out for her and checking over your shoulder. Why do this to yourself. She’s your mum and you clearly care deeply. You can’t just switch that off. It’ll spoil your day to see her stifling her misery/ faking a brave face/ getting overcome. Don’t do this to yourself. It’s your day. Hopefully the only wedding you’ll ever have. It’s about you and Dp not your dad, dads girlfriend- or in fact anyone else at all. Don’t invite trouble and avoid avoid avoid any unnecessary upset. Have a fabulous day Op.

The parents finally separated in 2022, which really isn't that long ago given they were likely together for a very long time.

When I told my mum I was getting married she demanded to bring her married lover to which I told her not a bloody chance because she was P'ing on the sanctity of marriage, obviouslyshe wasn't happy but she had a choice come to her daughter's wedding or not. Only you and your fiancé can decide who goes to your wedding if it ruffles feathers then you need to decide if you can deal with the fallout.

Good luck with your wedding planning x

It's not been as long as that, but I agree the mum needs counselling. Especially as the previous breakup seems to have been with them reuniting as she had a nervous breakdown.

Losing the plot at a new, completely unrelated new GF in this way is extreme. She isn't stealing any family either.