The first anniversary wasn't the worst. She was still numb. Still expecting to hear his voice, catch a whiff of him, or feel his arms slide around her in the middle of the night, but she was so numb it didn't hurt as much as she thought it would.
The second wasn't the worst, either. The numbness was still there, but there was work to be doing and Zoe had to wait until all the niou-se had been dealt with before she would allow herself to cry.
The worst was the third, when a beaming Kaylee announced that Simon had "knocked her up good and proper".
Later that night, over large amounts of alcohol, Zoe said "That should've been me, Cap'n." When Mal responded "You wanted Simon to knock you up?" she punched him in the face. It didn't make her feel better. Well, not a lot.
On the sixth anniversary, River showed up with a funny look, medical supplies, and a question.
And now here she was at the end of the day on the seventh anniversary, watching the sun set as she stood in the doorway of her very own place. She rubbed a hand across her belly and felt the baby kick in response. Her baby. Their baby - hers and Wash's - because River had figured out a way.