Saying "Dr Zhivago" is a tale of love set against the backdrop of the Russian revolution and the 3 wars around that time is, in my opinion, incorrect. It's a novel about the Russian revolution, WW1, the civil war, WW2, about communism and the bolsheviks, about the political changes and their effects on people, about the loss of individuality and the collapse of an ideal, etc. It's only because there are people that there is some love in it, the love story (or stories) isn't (or aren't) the focus.
I personally like the social, political part, which is very detailed and vivid, not the love part.
Update at 9.11pm: This makes "Dr Zhivago" by Boris Pasternak very similar to "The unbearable lightness of being" by Milan Kundera. A love story in a war would be "Gone with the wind" by Margaret Mitchell for example.