Standard ***** protocol is to throw undies in neighbors dumpster, not leave for the wife to wash and certainly find out her husband has the bowel control of an 18 month old.
Exceptions to this rule include but are not limited to: If underwear is some sort of "lucky" pair. You still live with your mom as she has likely known you're a nervous crapper for years and is also on to why you seem to go through tissues so quickly despite not having a cold. Neighbors garbage cans are not unaccessible, in which case you chuck those filthy shorts out the window on a gravel road.
Wife already knew of the incident, which means a later discovery will be met with "seriously, and then you do that?"