[he can't really voice why he feels like he'd never held Melody at all--possibly it's just his grief talking. At least with Amy he'd known her as real before she was replaced. With Melody, he knows she was already a ganger when he found her. He's never set eyes on the real baby Melody. So ... in his mind, the two situations are different. But grief instead of logic is still ruling him, and mostly it's anger and devastation that he was deceived not once, but twice--with the two most important people in his life.

And he can see the dawning horror in Amy, in the way her face drains of all color and then goes carefully blank, her body humming with tension. He's killing her, and it's killing him]

Because--because of the Doctor. They want to turn her into a weapon against him. That's what River said. [somehow, he manages to keep his poker face on as far as River is concerned] Kovarian, she, she thinks the Doctor's some great evil fearful--thing--that has to be stopped and she needs our baby to turn into a sodding weapon to do it!

[composure? Gone. His shit, he's losing it]

But I don't know why it had to be her! Why wouldn't anyone else work? Why did it have to be you, and our baby?!