BM Dilemma, need opinions girls!

Okay, so, I asked my entire bridal party right away..... with the exception of my brothers girlfriend. They have been together for over 3 years, and I love her, but, I wasn't sure. They have been on and off lately, and, I was worried that if something happened, it would be weird having her.

I talked to my brother about it, and he wanted me to ask her, I told him that if they break up, I'm not sure what will happen, that she probably won't be in it.... but, he really wanted me to ask her.

So, I asked her, she said yes, and she even went to try on dresses with us.

Now, they broke up, about a month ago.... they still talk, but are broken up. When they broke up, she told him she would still be in the wedding, and, he said, 'Well, maybe they don't want you in it.'

I'm in a weird position. I like her a lot, but, if they are broken up, I kind of don't want her in my wedding. But, I feel like that is kind of rude, since I already asked her..... so, I am not sure what to do.

Should I just leave it alone until it comes time to order the dresses in about a month and a half and see where things are, and maybe sit down with them and talk about it?

Anyone have any better suggestions?

TIA