It might spare her some pain - or it might just give her more. He's hoping for the former, but ultimately, it doesn't really matter what her reaction is. If she wants to know, she deserves to know. Especially at this moment, when she had every reason to believe she'd die without seeing any of her hopes realized.

Maybe in her future, when things go wrong, she can remember what's coming and take some hope from it. There were good times. There are probably still good times, for Scully on her own - he just doesn't know what they are.

"Okay," he says, and reaches for the box. He's practiced his lock-picking relatively recently - it's not a terrible way to distract himself, when he's up too late and has no hope of getting some rest. It still takes him a bit, but he gets it open within a minute or two. And then he sets the box on the bedspread, letting Scully be the one to lift the lid and sift through her life.