My thought: Why not write a love song.
However, if you have no musical or writing abilities (like me) then you should just visit songlyrics.com and search for a song. Maybe it's one that has special meaning, maybe it's one you just like. Then you can write it out, or type it out or maybe just take a line or two and give it to your Valentine. Voila - the perfect gift.
If you need a little inspiration here are a few example I found online:
|Found on Poppy talk|
|All You Need is Love note card by Texas Girl Designs on Etsy|
|Rainbow Connection - Custom Song art by Skårtshop|
|How Sweet it is by Creative Spark|