I mean I have a few anime girls that I really, really, unhealthily like a lot (pic related I guess) but I never let it dictate my life in anyway. It's just a fantasy, just a non-serious comfort of detachment from the real world.
I think that the whole one "waifu" thing is a little silly and that if you wanna like more than one character a lot you should just do it, but the whole point of having a waifu is just something to make yourself happy and if constricting yourself to one character is what makes you happy then you should go right ahead because it's your fantasy and you can do what you like.
I think this video is really good at addressing this topic:
http://www.youtube.com/watch?v=_YtwPPsBKGQ(fyi VN Kurisu is 10x better than anime Kurisu)
