According to another excerpt from the book, obtained by US media, Mr Trump used to boast that sleeping with his friends' wives made "life worth living".
"In pursuing a friend's wife, he would try to persuade the wife that her husband was perhaps not what she thought," Wolff quotes a Trump friend as saying.
He would invite the wife to secretly listen on speakerphone to a conversation that Mr Trump would have in his office with her husband, according to the book.
Mr Trump would allegedly engage in sexual banter with the husband in the hope that he might say something indiscreet, asking questions such as: "Do you still like having sex with your wife? How often?"