Happened with some characters. Examples would be Morgiana and Kaneki. I used to love them and I still like them, but not as much as I used to when I watched their animes.

Er— no.... Never happened. Once I love a character, there's no goin' back XD

I mean, I suppose it can get to a point where I don't really think about them as often, but once I recall their existence, that deep love I have for them is still there. The love still exists, whether it's cognitively acknowledged or not.

Tsubaki from Soul Eater, Ken Kaneki from Tokyo Ghoul, Inori from Guilty Crown, and Celty from Durarara!!

Yeah, I think this normally happens especially when you've watched too many anime's and you wanted to make a top 10 list that you've forgotten some of the characters you used to like.

I may not fangirl as much as I used to but this doesn't mean I don't like the character anymore.

Tsubaki from Soul Eater, Anri and Mikado from Durarara, Sweden from Hetalia, Yukine from Noragami, Shikamaru from Naruto, Nagisa from Assassination Classroom, Rin from Free, and Nanao from Tsurune

oh my lord that's more than I thought

honestly how could anybody be so cruel? That only shows the character didn't deserve their love in my opinion...

^ 'be so cruel'. Because liking a character less than you originally did is making you a cruel person. Right xD
Go look the definition of cruel, buddy.