Why was Lucien so inconsistent?

I've been rereading acotar recently, and I really don't understand what happened to Lucien. Acotar Lucien was a spitfire. He was a shameless flirt, he spat at Tamlin's feet, and spoke his mind. So why is acomaf Lucien such a pushover? He's basically walking on eggshells around Tamlin, and allowing him to mistreat Feyre, and he seems much more awkward and timid in general.