Given the following context:

British couple Nigel and Fiona Dobson are on a Mediterranean cruise ship to Istanbul en route to India. They encounter a beautiful French woman, Mimi, and that night Nigel meets her while dancing alone in the ship's bar. Later Nigel meets her much older and disabled American husband Oscar, who is acerbic and cynical, having been jaded and a failure as a writer. 
Oscar invites Nigel to his cabin where he tells Nigel in great detail how he and Mimi first met on a bus in Paris and fell passionately in love. Nigel relates all to Fiona. Both are appalled by Oscar's exhibitionism, but Nigel is also fascinated by Mimi, who provokes him. Later, Oscar narrates how they explored bondage, sadomasochism, and voyeurism. As a contrast to their sexual adventurousness, we see Nigel and Fiona meeting a distinguished Indian gentleman, Mr. Singh, who is traveling with his little daughter Amrita.
Invited by Mimi, Nigel, escaping from a bridge game, goes to meet her in her cabin, but it turns out she and Oscar have played a joke on him. Nigel wants to leave, but another session unfolds, with Oscar describing how their hate/love relationship developed. Bored, he tried to break up, but Mimi begged him to let her live with him under any conditions. He complied, but started to explore sadistic fantasies at her expense, humiliating her in public. When Mimi became pregnant, he made her have an abortion, saying that he would be a terrible father. When he visited her in hospital, he was shocked by her condition and almost relented in his attempts to drive her away. He promised her a holiday in the Caribbean, but he got off the plane just before take off. Mimi departed alone, crying.

answer the following question:

Which person got Mimi pregnant? 

Nigel