I think marie is right. My second husband had a book of mine, and for at least a few years after I moved out, moved across the country, divorced him, he would call me once every several months and ask if I still wanted the damn book. I always said, "Sure, I want it." I never expected to get it, and I never have. It wasn't even a big deal of a book--it's one I could easily order another copy of, online.
I wouldn't count on getting it back, unless you wanted the drama of taking him to court over it. And even then, I would have my doubts you'd ever get it.