The Fountainhead Part 2, Chapter 14
Keating is packing for his trip tomorrow to marry Katie when Dominique visits him. Cutting to what she wants, she asks him to marry her. She tells him he has to say yes or no because her car is downstairs and they have to do it now, if at all. Knowing what he wants, Peter accepts. They go downstairs, drive to a judge, marry with the judge's wife and a neighbor as witnesses, and drive back. During the ride back, Keating realizes that he wants her physically, and is finally allowed to have those thoughts now. Dominique says they will live in his apartment, and she will have her things sent there tomorrow. She drops him off, and drives to Roark.
Roark hasn't seen Dominique since the trial. She smiles at him; they go to each other and spend the night making love. In the morning, she sees that he is drained and they seem to have exchanged energies. She tells him she loves him and then tells him that she married Peter Keating. She explains why; she has to make herself miserable in the world because otherwise she'd be desecrating the fact that Howard exists. He asks her what she would do if he told her to annul the marriage to Keating and marry him; she says she would obey. He tells her that's why he couldn't ask her to do that, because then he would become her life and they would end up not loving each other anymore. He tells her he loves her selfishly and that's the only way he would want to be loved. He says that the world won't destroy her, and that someday she will come back to him.