Neal is used to wanting things he shouldn't have.
It's no big change for him to silently plan and scheme and fantasize ways of getting something that he wants, something that, should he actually get it, might very well prove his undoing. He's been hunted down and beaten up and nearly killed many times, because of something he wanted that someone else thought he shouldn't have - or wanted for themselves.
But this - this is different.
This is the most dangerous prize of all.
He watches from the shadows as they whisper together, kissing softly in the candlelight, laughing quietly over some private joke. They think he's asleep - think he's shut away in the guest bedroom, resting up for the early job he and Peter have the next morning.
But he's drawn to them, drawn to the affection and the warmth in their soft words, drawn to the easy intimacy in the touches they share - drawn to something breathtakingly beautiful that he can't steal, can't replicate - can't have.
But he aches for it, and finds that more and more with every passing day, he can't make himself stay away - even if he knows that eventually, he's going to end up burned.