I'm gonna answer you in small part because Damn Wattpad won't let me put my whole comment on my own story lol!
Dav-Vel never thought about killing Diana. He's really confused about his feelings for her, something that had never happened to him before, to the point that when he arrived on Amazon Island, he said that "I could go there and force my way in, destroying everything in my path," but he didn't do it out of respect. As for acting like a god... well, gods can't stop acting like what they are. Dav-Vel, even if he hates them, can't change his nature.