Difficult mother and sister in law :(

Oh no, hassle with the in-laws is the worst. But very common during wedding planning, it seems!

Is your MIL-to-be cross about her daughter not being your maid of honour, or is she cross about whatever it was you fell out with her daughter about? You'll need to get to the root of why she's not coming to the wedding before you can try to fix things. It really depends on what your argument with SIL was about. Can you see you and SIL making up if she apologises? Or has she really crossed a line about something? It sounds like she has if she's been calling you names! In which case you're completely within your rights not to have her as a BM, and your MIL-to-be has no right to argue. Maybe your MIL doesn't know the whole story and she's only going on what your SIL has told her. I would get your OH to step in here to try to smooth things over.

x

If MIL is taking sides then it may be less stressful for you to consider an overseas wedding. That would avoid the family hassle.
You could pay for your parents to go and it would still cost less than having a big wedding in the UK

It may be worth calling your FSIL to talk things through. It may bring up what happened previously but sometimes it is easier to clear the air before you can move on. If you can make things smoother with her, the your FMIL may take a step back as she is being rather extreme about it. Mothers apparently find it very hard to not be at their children's wedding so I wouldn't worry too much about this yet unless you are getting married in the next couple of months.

You can never please everyone when planning a wedding, me and a lot of other people on here will tell you the same. You will always tread on someone's toes as hard as you try not to.