Seregil couldn't deny the pity in his eyes initially, but now that he's watching Alec, he realized it isn't what the other man needs. So he closes the book and sets it to the side before pulling himself up to sit next to him.

"You have a choice now." Not that he's saying that Alec should do anything with him. He's just trying to remind the other man that he does have that choice right now. That he will have it so long as Seregil can make sure of it.