He feels silly saying it, but Bill is nothing if not honest to a fault sometimes.

"I worry that you'll grow bored with me and leave. Not right away, but eventually."

It's not that he doubts her love for him.

It's that he has little faith in circumstance. That's something the Death Eaters took away from him.

"The good side is that it makes me realise that every moment we have together is so very precious."

Live every day as if it was your last.