If your Honey is inside then holiday cards, birthdays etc have to be planned in advance so they arrive at the jail or pen and make it through the mailroom and arrive in time.
I like to send multiples. Sweet, romantic, insightful, caring and funny. Over kill? Maybe on the outside but on the inside things are harder and what's left unsaid can hurt.
Funny needs to be funny yet not hurtful. They need to see the love through it. I didn't find anything that said funny for Valentine's in that right way. Then I remembered St Valentine was in jail too and then my inspiration came.
Dear Honey
"So your impersonating St. Valentine for me this year?"
"Very romantic <3 but let's say next year you just take me to the movies"
"Love Always Your Honey Bunny"
See the reference to next year? A little note to remind him I see there being a next year. And its a suggestion not a "you better or else".