How do i uninvite my toxic sister in law ...

Your wedding is almost two years away. How can you uninvite someone when no one has been invited yet?

I would talk to your brother about this privately. You are right that not inviting your brother's wife runs the risk of your brother not being at your wedding. Only you can decide if that is worth the risk.

As for the flower girl thing, I would stop engaging with your sister-in-law about this (about everything wedding-related in fact). She already doesn't like you, so this won't change anything. But not having to keep having that argument will bring you some peace of mind.

And also, I agree that your wedding is so far in the future that you don't need to worry about sending invitations (and therefore having a difficult conversation about who isn't invited) for ages (COVID has nothing to with this. Guest numbers can never be set in stone until a reasonable RSVP window before the wedding date.)

You can't not invite your brother's wife. She's your brother's wife. He married her, presumably he loves her. Yes, it would look horrible. I completely understand toxic relatives, by blood or by marriage, but all you can do is invite them both, or not invite either. Even if you were to figure out a way to only invite him, there's is no way his wife would let him go without her, if she is abusive as you say.

As to the wedding party, that is your decision, and if she brings it up again just politely say that you and your FH have made your selections, and they are final. Say you don't want the bridal party size to get out of hand, or or just say no. You don't need to explain yourself to her.

Sorry to say, but I think that unless you are ok with your brother not attending, you're going to have to invite her. Chances are you won't see much of her anyway, since you'll be busy with festivities.

Agreed. Get brother on board and just don't invite her.

Lets be honest you are picking sides if you are having at least 2 nephews in your wedding but not niece. So that is actually true. You are not obligated to have it and you shouldn't be guilted about it, but she isn't wrong. You are making a judgement call because you don't like her and you do like your fiancés nephews parents.

There is absolutely no way to not invite your brothers wife. Any spouse worth their salt would refuse to attend a family wedding in which their spouse was not invited. Also, by not inviting her you are impacting your relationship with your brother for the rest of your life. It also puts the rest of your family in a terrible position. If they all support you then it may ruin their relationship with your brother as well. Do you want to have contact with your niece in the future? If you alienate her mother you won't. If she wasn't your nieces mother would you make her a flower girl?

This is a complicated situation with a lot of consequences riding on it. I would think three times before making any definitive plans. Discuss with your future spouse your vision of family life after the wedding and how you will accomplish this. I am not saying you are wrong for not wanting her there. I actually think the opposite, but life is messy and imperfect. Sometimes you have to do things because it is the best way forward, not because its the best way. Only you and your spouse can make that decision.

Also as an aside, your brother doesn't sound like a saint if he is telling people personal stuff about his wife. And you said he has said it many times. How will his daughter feel when this comes out to her...because if it is so well known then clearly people in the family are not discreet. They sound like they have a mutually dysfunctional relationship