I am a home wrecker

So long story shortish. my sister got married recently. We are a very close family and so is her husbands family so we all clicked really well. I never thought of her BIL as anything other than a brother. Not once did the thought cross my mind. I am happily married. And now expecting our first child. Well her BIL wife went off the deep end and started accusing him of having an affair with me and two other girls. Mainly me. I don’t know what I ever did to even make her think this about me it’s not me at all. She said we slept together on my sisters wedding night. Her and my husband were both there. Anyway they are now divorced because she is just bat shit crazy (more shit happened other than this “affair” we had) and he now has a girlfriend we all love. Anyway the actual point of this story my sister is having a Halloween party this weekend and I was trying to get my husband to dress up like the milk man since I’m pregnant and he said no and we both said Dillon at the same time. My husband will be the unsuspecting husband. My sisters BIL will be the milk man one of our other friends will be the mail man and she is going to have her husband be the neighbor and her the unsuspecting wife😂 this was a big thing everyone knew about our “affair” but they also knew there was no way in hell that really happened.