J.✰.
Normally, a couple gift would be fine, but if your husband wants to really get this friend a book, then just let him. Get her a funny tear-away-page-a-day calendar (who can't use that?) or a small piece of jewelry from James Avery. I like the mani-pedi idea. Or the book for her gift idea. The sky's the limit. But tell your husband - next year, it'd be easier if we just got a 'couples' gift.