Bringing in the theory
Coming from a psychology perspective, I see NRE as an attachment-forming device. It's the same (brain chemistry-wise) as seeing a baby for the first time and wanting to scoop it up and keep it safe. The infatuation and affection of that period secures people a bit and helps to ensure that the couple is invested enough to stick it out through colic nights (or arguments about the toilet seat).
No clue whether that's positive or negative, but it's still my two cents.
"I was thorough when I looked for you, and I feel justified lying in your arms." - Chasing Amy