I know one of the characteristics of realistic works is they are mostly formulated as some independent studies of the life of society but, at the same time, I realise that the dominant approach to art in that time was to see it pragmatically, as a way to share your worldview.
Anna Karenina seems to describe lives of two relationships: Once (in the relationship between Anna Karenina and Vronsky) the characters fell into the natural desire for the "natural love" (éros, so to speak) and it ended badly and once, in the relationship of Kitty and Levin, the characters seemed to contemplate about their relationship for a while and they seemed to make a happy, overall fulfilled couple.
So we can see the book is pretty far from describing the naturalistic hopelessness and straightforward critique of the opportunistic society. Rather, I feel like Tolstoy thus argues by the natural nature of love for more liberal approach of society (the conservatism of Alexey and Mrs. Scherbatska had been devastating).
But is it really possible that Leo Tolstoy intended to make the story that symbolic? Can we see there some kind of model of love Tolstoy is trying to describe?