Ok sorry I'm gonna open the wound again but
Do you realize that when Stolas said he wanted to end their deal, Blitz didn't get angry but implores him bcs of the book.
But AFTER getting the crystal, his anger explodes because Stolas talks to him about feelings.
He could have got angry right away bcs it would ruin his business, or just take the crystal and don't bother about the rest, but no, he lashed out because the poor guy thinks Stolas is joking with his feelings, and it affects him because HE CARES FOR HIM.
And he refuses to believe Stolas or anyone could love him so it HURTS HIM.