You are familiar with the term "imprinting," i'd imagine? Snakes do actually have that ability as they tend to imprint upon favorite prey items.
They have a capability, as such, to associate a specific smell with safety and warmth. He feels content to be curled up around me, or chilling out on me. if it was just warmth, he'd go hide under my heat blanket when I have him out.
I wouldn't go as far as to say he loves me like I love him. Or how I love my cat (rip) and my cat loved me (maybe...). But he has definitely shown that he is quite content and prefers to be on me than any of the other less lively but equally warm things.
its not a human emotion. This is a very basic "emotion" that the majority of all creatures feel. With little exception.