Oops, it doesn't look like 'get cheated on day' is a national day..

Other days

aloxolt

Aloxolt Day
reading

Reading Day
mean girls

Mean Girls Day
martini

Martini Day
tulip

Tulip Day
frozen yogurt

Frozen Yogurt Day
bow tie

Bow Tie Day
cursing

Cursing Day
artists

Artists Day
boy friend

Boy Friend Day