"I adore you" is not a silly thing to say to your wife.
"You are precious to me" is not stupid.

My husband of 29 years emails me love songs.
He made a decision to court me on a daily basis, a long time ago ...

As H likes to say
"Happy wife, happy life".

I really don't give a chit if it feels weird, or makes you uncomfortable to be over-the-top expressive towards my friend, your wife. I don't really care if you don't feel ready, or sincere.

Do it.
Every day.