One thing i remember noticing in Dostoevsky's work is that he appears to have at the same time a pre-occupation with beauty, and also one which is not analysed at all.
Some examples of beauty playing a part in his characters:
Raskolnicov is described as very beautiful. I always thought that he made it that way so as to have the readers avoid some explanation of his misery by means of frustration with women.
In the "pitiful tale" there is a character who is almost only described as "very good looking boy". He acts in an angelic way.
The narrator of The Underground introduces himself by claiming he is repulsive (i trust physically as well as ethically).
In the vast ocean of his work such a theme perhaps can go utterly un-noticed. It has been years since i read most of it, but there are other characters who are physically ugly, such as Marmeladov, and they get diminished to the point of being treated like animals.
Also i do not recall any clear passage of adoration of beauty. Unlike in Tolstoi's work, were the human form is often mentioned and adored, or even if it isnt then there is some very clear occupation in the story about this.
In Dostoevsky it seems that the form has some hidden meaning, perhaps some meaning he didnt feel comfortable with.
This could be one of the motifs in his work, perhaps not as pronounced as others, but still existant