I've seen people having their Waifus in their sig, or mention that "these are my waifus" in posts, etc. What I want to know is how you can call someone your waifu... and then call someone else your waifu. In my opinion, the reverence required for someone to be your Waifu cannot be applied to more than one character. When someone says, "Yuki Nagato is mai Waifu", you know that they will defend every last one of her actions, features, and personality traits to their dying breath. However, when I see someone post "Mai Waifus:" and has a list of six or seven characters, all I get out of it is "that person likes those characters". It diminishes the implied value you hold for your Waifu.
How do you feel about multiple Waifus?
(For the record, Luka Megurine is Mai Waifu. Those unwise enough to criticize her will be annihilated with extreme prejudice.)