LAY-na? or LEE-na? Either way, I think it could stand on its own.
However, you could also use
AlenaElenaHelenaKalenaMadalenaMagdalenaMalena MarilenaMilenaOlenawith the nickname
Lena.
On a related note: My cousin named her daughter
Lina this summer. I think it works.
I love that your fiance has such strong feelings about names....two namenerds getting married! :)