Shower slip up.... ( a little long)

Yesterday I was at my friends daughter's communion and while we were all hanging out, my other friend was talking about her daughter's MIL, who had called her to plan the baby shower. The date of her daughter's baby shower is 5/21, so she was joking around saying that she will be away that weekend (this is her daughters second baby and she is not thrilled about it ...long story) So then her husband pipes up and says, of course she won't be away because its the day after my shower. Everyone's face dropped and if my girlfriend could have killed her husband right there she would have. I felt so bad, but so relieved to know when it was. He couldn't stop apologizing.

One of my BMs was there and didn't hear him say it but found out and was so upset. I feel really bad, do I pretend I was drunk and I didn't hear it or what? My FI doesn't know cause he would be sooooooo sad, he has been like the biggest kid wanting me to be surprised.

Maybe, it was a plot because I have been trying to get it out of anyone who would tell me when my shower is.

Any thoughts ladies? TIA.