SciFi and Fantasy Book Club discussion

I think this is an older YA book which is part of a trilogy. I was only able to read the first one because that was all that my school library had at the time, but it was about a girl who had to become one of the brides of a vampire. He had six or seven wives who had all become wraiths, and she (the latest) was supposed to spin a thread out of thin air. There were also various animals which she gave fruit to, which turned into hearts, and a sea made out of blue sand, not water. Very vivid and strange imagery and I always wondered what happened in the end!

I wonder if this is Meredith Ann Pierce's Darkangel trilogy

Definitely Meredith Ann Pierce's trilogy, starting with The Darkangel. Loved those books when I was a kid. :)

Thank you sooo much!! You guys are amazing -- I think that's it! Now I'm going to rush off and buy them ;)