"We'll see," she answers, more to herself as she moves to unlock the door, "'m-- opening the door. But b'fore I do... 'm-- really sorry."

Sorry that she's not told him, yes, but also sorry that the fact she didn't is likely about to change his mind on whether or not he still loves her.

She opens the door, then, shaking so hard it's almost difficult. She's going to back away as far as physically possible once he makes the move to come in.

It's going to be impossible to hide just how very pregnant she is, after all, and it's impossible now for her to be any less terrified, quiet tears still streaming down her face.