Another idea might be (and this I'm basing on your wanting to read but doing other things in your free time instead) to start with very short books - a novelette or short story collection or, at most, a novella. They may not be the books you're currently interested in reading but may help to form a habit and will give you that 'reward' of finishing a book quickly which could help all by itself, giving you that feeling that you've done it once, now you can do it again.