Oops, it doesn't look like 'i fucked your girlfriend day' is a national day..

Other days

Tell Ur Crush You Like Them Day

Fiancee Day

African Immigrant And Refugee Hiv And Hep Awareness Day

Tell A Fairytale Day

Cuddle Up Day

Azonto Is Acceptable Day

Martini Day

Get Funky Day

Ormille Day

Unicorn Day