In Doctor Zhivago, Pasternak explores the tension between love and responsibility, two forms of feeling that don’t always align. This discrepancy is established early on in the novel in the contrast between Lara and Komarovsky’s fraught affair and its aftermath, and Yuri and Tonya’s measured, domestic relationship. Whereas Lara submits to her passions—and, of course, to the will of a much older and more powerful man, upon whom her family depends—Yuri Andreevich marries Tonya out of a sense of duty as well as genuine love, having promised his foster mother Anna Ivanovna to take care of her. The importance of the origins of their marriage only become clear when Yuri Andreevich’s powerful passion for Lara takes hold, emphasizing the difference between these kinds of love—much to Tonya’s dismay. Nevertheless, Tonya is not necessarily correct when she accuses Yuri Andreevich of not loving her. Love and responsibility can coexist and be mutually destructive, depending on the circumstances, but Yuri Andreevich’s love for Tonya is gradually overshadowed by the sense of obligation he feels to her and his family. Similarly, Komarovsky’s passionate and manipulative desire for Lara matures into a sense of responsibility for her which motivates him to first support her after she attempts to kill him and then to help her escape Yuriatin. Of course, it is likely that Komarovsky’s baser feelings guide these noble actions too, at least in part. Ultimately, then, the novel suggests that love and responsibility have overlapping and shifting roles in our lives and relationships. For this reason, it’s largely impossible for a person to cleanly separate these emotions from each other, as much as they may try to do so.
Love and Responsibility ThemeTracker

Love and Responsibility Quotes in Doctor Zhivago
If mama finds out, she’ll kill her. Kill her and then take her own life.
How did it happen? How could it happen? Now it’s too late. She should have thought earlier.
Now she’s—what’s it called?—now she’s-a fallen woman. She’s a woman from a French novel, and tomorrow she will go to school and sit at the same desk with those girls, who, compared to her, are still unweaned babies. Lord, Lord, how could it happen!
A great and powerful feeling is sometimes met with in the world. There is always an admixture of pity in it. The object of our adoration seems the more the victim to us, the more we love. In some men compassion for a woman goes beyond all conceivable limits. Their responsiveness places her in unrealizable positions, not to be found in the world, existing only in imagination, and on account of her they are jealous of the surrounding air, of the laws of nature, of the millennia that went by before her.
There outside is the spring evening. The air is all marked with sounds. The voices of children playing are scattered at various distances, as if to signify that the space is alive throughout. And this expanse is Russia, his incomparable one, renowned far and wide, famous mother, martyr, stubborn, muddle-headed, whimsical, adored, with her eternally majestic and disastrous escapades, which can never be foreseen! Oh, how sweet it is to exist! How sweet to live in the world and love life! Oh, how one always longs to say thank you to life itself, to existence itself, to say it right in their faces!
And that is what Lara is. It is impossible to talk to them, but she is their representative, their expression, the gift of hearing and speech, given to the voiceless principles of existence.
Outside the window it began to snow. Wind carried the snow obliquely, ever faster and ever denser, as if trying all the while to make up for something, and the way Yuri Andreevich stared ahead of him through the window was as if it were not snow falling but the continued reading of Tonya’s letter, and not dry starlike flakes that raced and flashed, but small spaces of white paper between small black letters, white, white, endless, endless.
Yuri Andreevich involuntarily moaned and clutched his chest. He felt faint, made several hobbling steps towards the couch, and collapsed on it unconscious.
“If they have time, if the sun doesn’t set beforehand” (he wouldn’t be able to see them in the darkness), “they’ll flash by one more time, the last one now, on the other side of the ravine, in the clearing where the wolves stood two nights ago.”
And now this moment came and went. The dark crimson sun still rounded over the blue line of the snowdrifts. The snow greedily absorbed the pineapple sweetness the sun poured into it. And now they appeared, swept by, raced off. “Farewell, Lara, till we meet in the other world, farewell, my beauty, farewell, my fathomless, inexhaustible, eternal joy.” And now they vanished. “I’ll never see you again, never, never in my life, I’ll never see you again.”