As is the rule around WinCustomize there are always lots of skins available to download to customizie your desktop for just about any Holiday or occasion. Valentine's Day in no exception. 
I did two searches and here is what I found.
Valentines:
https://www.wincustomize.com/skins.aspx?search=valentine&p=1
Cupid:
https://www.wincustomize.com/skins.aspx?search=Cupid
This will take care of the desktop, you better get to the store and get a gift if you haven't yet. 
