Does my Fiancé's Brother's Girlfriend have to come to my wedding?

How is this even a question. This is the person he has chosen to be with, they are a social unit now, a pair, you no longer get one with out the other no matter how much you dislike her. I would encourage you not to exclude her from things in the future, not just wedding related but any events or it will drive FBIL away, I guarantee it.

Yup!

Yes she is invited

Yes you do. Sorry :/ I know that's not what you want to hear but you won't be around her all the time. I had a similar situation so I feel you. You have time also so don't worry about it things could change.

He should be getting a plus one - they've been dating three years!

How would you feel if they were getting married and you weren't invited? So what if you don't get along, put on your big girl pants and be an adult. Life is literally about dealing with people you don't get along with.

All social units have to be invited together to the wedding.

Whether you like her or not, they are in a relationship...she should gets an invite!

If you want to get to know your FBIL better, I'd suggest you dump this idea and never mention it again. The quickest way to ruin everything -- and I mean him stepping down from being your FH's best man -- is to exclude his girlfriend of three years from your wedding.

It really doesn't matter if you like her or not -- he loves her, and if things progress and he marries her, the woman you wanted to exclude from your wedding -- well, you can prepare yourself for some very icy holiday dinners...forever.

Very, very bad idea.

Yes but just put her in the back of the room where you won't have to deal with her. I would just do a couples table for you and husband

That's an awful idea Karebear, she would then also be shoving FBIL in the back of the room as well which I'm sure his family would appreciate

Yes you must invite her.

Yes

I understand why you don't want her there but it would show disrespect to FBIL to not invite her as they are a couple, not simply a plus one.

You know the answer.

Karebear, that was bad advice. Her boyfriend is the Best Man, a VIP, the guy in the tux making a speech and a toast, the guy at Table One. You cannot seriously suggest that his girlfriend be relegated to the back of the room. Wow.

You don't put her in the back of the room. That was bad advice, Karebear.

Nothing says "I'm petty and despise your presence!" more than that, especially if her boyfriend, the Best Man and a wedding VIP, is seated at the head table.

And even if they are seated together, guess what looks weird? The Best Man sitting in the back of the room at Table 19.

And guess who will be doing a lot of talking about that either way? The girlfriend in question, the Best Man, the guests, and so on.

I understand the feeling as I Loath or best mans girlfriend! But they are dating so she is invited. Sometimes you just have to suck it up.

Yes... she needs an invite

You have to invite her. Even if you don't extend a formal invitation to her, he will bring her.