4.Rip "Feb. 14" out of all of your calendars. Then show your partner that there was no way you could have remembered yesterday was Valentine's Day, as it literally isn't even in any of your calendars.
5.Apologize and then hand your lover a gift card to an American quick-service fast-food sandwich restaurant chain.
6.Put the excuse in a poem.
7.Use a vocoder to relay your excuse.
8.Do something worse than forgetting Valentine's Day so that forgetting Valentine's Day, by comparison to this awful thing, seems like no big deal at all!