User blog comment:27finnsprincess/The Talk About Marcy and Ice King.../@comment-5435219-20121014170753

I think that Marceline and Ice King DO share a special relationship, but not a romantic one. Maybe Simon was like a father-figure to her, since she has such a strained relationship with her dad. They probably know a lot about each other, but then ice king went crazy and he may have done something to cause Marceline to stop associating with him.