Bwahahaha you sound like me.
I have to agree that it was kind of an error in judgment for the bride-to-be to place your husband with one of his ex’s. I know how I feel about my DH’s ex and I would probably pitch a hissy fit if I found out they were walking down the aisle together in a wedding. But, then again, your circumstances may be different from mine. I have quite a few reasons to dislike my husband’s ex. But if it truly makes you uncomfortable then speak up. It may be her day, but this is your marriage.