My Mother-In-Law Demanded To Be My Maid Of Honor. When She Showed Up In A White Wedding Dress, I Did This

My mother-in-law showed up to my wedding in a wedding dress. I should have known better when she demanded to be my bridesmaid as soon as we announced our engagement; she had never liked me. However, nothing could have prepared me for seeing my mother-in-law, dressed in an all-white gown, standing at the altar as I entered the church. 

But that wasn't all... What she did next made me do something I should have regret about, but she deserved it.