Didn't you know? Animu girls are cloned. Whenever someone claims a waifu, another clone is made to cater to a man's needs.
Fancy claiming Orihime from Bleach as a waifu? POOF cloned. When a man becomes bored his waifu, she becomes homeless. A waifu is for life, not just for Christmas.
tl;dr
[color=red]
[size=29]OUR WAIFUS ARE CLONES
YOUR ARGUEMENT IS INVALID[/h][/color]
Example of a clone