To tell my sister she can’t bring her husband to my wedding?

Yes even having explained more it is still a really petty reason to not invite him tbh

The responses on this thread are overwhelmingly in favour of inviting BIL. It doesn’t really matter how much more explaining you do on Mumsnet, OP. It’s a tough dilemma for you but your fiancée must bear in mind that BIL is likely to keep well out of the way at your wedding (if he has half a brain) and it will save a family rift in the long run. The alternative is awkward family gatherings for the foreseeable future which will be worse.

I would invite him. My parent caused a family rift by not inviting sister to wedding. They reconciled after 20 years and both had really missed each other, shortly after sister died. Such a waste.

Why is there a smaller family chat that includes your fiancé but not bil? Who started that?
It seems really weird that there's a second group chat that excludes your BIL. It makes sense if there's a chat that has in-laws included and a separate one with you, mom, and sisters but your fiancé shouldn't be in that chat.

From everything you've posted your fiancé seems to be the biggest problem.

Don't invite him. Explain to your sister that invitations have to be agreed by both you and your partner as you each have equal say. Let her decide what to do. If she chooses to attach meaning to that, that isn't there, that's not your problem.

Sadly if you don’t invite him the comment he made to your daughter will likely become true.

The whole argument is really silly with lots of people making little mistakes that led to him being uninvited although I do think it’s strange he would jump to the conclusion that he was deliberately not excluded if there had only been good relations before this.

I understand you considering how your finance would feel having someone she dislikes on her wedding day but do wonder how much it would hurt you to have someone you love not there?

That’s the crux of it really

is her desire to not have someone she doesn’t really like there more important than you having someone you love dearly there?

Trivial argument that will last forever if you don't invite him. your Fiancée will probably not see that much of him at the wedding. Ask her to put you first.

Your fiance is controlling. This should be your main issue

Invite him. Arrange the seating plan so he is nowhere near you. You can easily avoid him on the day aside from a brief thank you for coming. I managed to do this with guests I wasn't as close to at my wedding and their presence spoiled nothing. It also avoided unnecessary arguments down the line.

On the day you will just be distracted by your close friends and family, and happy to find all the planning has paid off.

Well, as others have pointed out, if he is uninvited it will cause issues with your sister...you will see her less and so will your daughter. And all because your fiance won't act like a grown up. She punishes him, your sister, you, knock on to rest of family at future gatherings. So his prophecy will be fulfilled.

Your finance is being deeply unreasonable to threaten not to marry you over this. She can invite who she wants her side, he is on yours. Tough.

So, essentially, there was a tiff because a family member, understandably, felt excluded.
Your partner has blown this into such an epic drama that she’s considering not marrying you if this family member comes to your wedding?
This lady that loves you enough to spend forever with you is happy to exclude by extension your own sister from your wedding?
Sorry, I think your fiancée sounds awful.

Actually, I think I’d flip this on the head. I’d explain to my fiancée that I would have to reconsider the marriage if such a stupid spat meant you couldn’t have your sister at your own wedding.

He apologised, she apologised, why does he need to do more specific apologising?

He shouldn’t have said that to your daughter, tell him that but invite him.

Your fiancée sounds controlling and a bit of a drama queen.

I have a different perspective to most on this thread, informed by your latest update clarifying the argument OP, but also by your earlier posts.

There is a separate group chat with only nuclear family members - normal
Your sister missed the messages inviting them as a couple to the BBQ - not a big issue
Your sister didn’t tell BIL about the invite - not a big deal, but certainly not your fiancée’s fault
BIL lost his shit about thinking he had not been invited to the BBQ and started sending angry messages - ridiculous escalation
BIL called your fiancée a “controlling bitch” when she’d done nothing wrong - abusive, misogynistic escalation
BIL then dragged your nine year old child into the argument - manipulative, controlling and really nasty.

I really don’t understand the comments calling your fiancée controlling. She apologised for her part in the argument and for insulting him back, while he has never apologised for calling her a bitch. It seems to me like he’s throwing his weight around and is a nasty piece of work. He expects her to suck up his shitty, aggressive behaviour - not for the first time maybe if you already dislike him?

I can absolutely see why she’s uncomfortable having him at the wedding. Did you stand up for her when he lashed out and called her a bitch? Or did you leave her to deal with him alone, when she had done nothing wrong and he instigated a nasty fight?

We had people at our wedding that my husband or I were lukewarm on, that’s normal. We did not have anyone at our wedding who’d verbally abused either of us because their partner didn’t tell them about a BBQ they were invited to. Ridiculous.

You said you are close to your sister but you are allowing your partner too exclude her husband over an argument wich will in turn exclude your sister. Yes there was an argument so what family's argue.
I personally feel you need to be very careful if your partner gets her way this time by making threats that is not a good foundation for marriage and what happens if your parents ,other siblings or friends annoy her will they be excluded too.
My brother is getting married next year we have several family members who dont get on he's just putting them on different tables.
Is everybody else involved in the argument excluded too because if not then yes it does look personal and it will look that way too your sister.
Have you tried speaking to him directly and do you know why he reacted that way and what your partner said to him? There is always two sides to every story.

No the separate group chat with the nuclear family also has the fiancée. Which is a bit odd

Yabvvu.
your sister’s husband should be invited.
your fiancée sounds controlling and like she wants to cut you off from family. She needs to back off and suck it up. Not all family are people she would choose to be friends with but she can still be civil. If she loves you she should be making more effort. .

If BIL has a problem with there being a group chat that doesn’t include him, and his wife not passing on messages, he can raise that calmly. “Oh no, we missed this invite, can you add me so we don’t miss the next one!” Would be a normal way to handle that.

Flying off the handle and scapegoating the fiancée is beyond odd IMO, it is suspicious. There was absolutely no need for him to get so angry and abusive. It’s just a BBQ, and he’s dragged a nine year old child into a needless row.

Oh for sure the whole thing is odd. But I don’t think it’s ’not invited to the wedding’ odd

I don’t understand the whole exclusion from a family BBQ.
If any family member sent me or my dh an invite, we would rightly assume us as a whole family were invited.
The same as if we invited my siblings or DHs siblings, their partners and kids would automatically be included (without naming everyone).

Your sisters dh not being included to a BBQ is weird.

Just invite him to the wedding, don’t cause more unnecessary drama.

Yeah I think for me it comes down to a few things - him trying to whip up the rest of the family, including OP’s child, against the fiancée, and how OP has backed (or not) her fiancée in this.

If I’m the fiancée here, and my future in law loses his shit at me about this, the reaction of everyone around me is instructive. My partner and her family say “it’s a shame BIL missed out but unacceptable to overreact like this and we don’t think badly of Fiancée because of it” - that gives me some comfort. If it’s “oh well families fight” or “his precious male ego has been wounded so it’s fine for him to call Fiancée a bitch” then I’m wondering if this is really a family I want to marry into.

He wasn’t excluded, his wife didn’t pass on the messages (and sounds like they had other plans anyway!)

I absolutely wouldn't want someone who'd called me a controlling bitch at my wedding.

@Omegaez, surely the two most important people to you are your daughter and your fiancée? He has treated both of them awfully. If your sister can't see why you wouldn't want him at your wedding after that, then I'm afraid you'll have to accept you will be less close going forward.

Not sure I'd want someone at my wedding who called me a controlling bitch!

Did he not understand that he was invited but his wife had missed the message?

He knows your fiance better than strangers on the internet and he thinks she's controlling. Maybe you just can't see it. You seem to be focused on working out who is wrong in this situation when they are both as bad as each other.

But they have both apologised so they should be able to leave it there and move on. Your fiance is the one being stubborn, even to the point of saying she won't marry you.

What do you think of her saying that? Do you think it's reasonable? Do you think it's loving and reassuring?

Forget your BIL, he's not the problem.