I am also in the process of discarding books. I've guesstimated there's at least 5000 books in this house. Many are books I've read several times, but doubt I'll read again. Lots of children's books and books for homeschooling. Many were the same authors in your boxes, that my husband had liked and I did not.
I've very seldom discarded books in the past. This is a major purge for me.