Two wives of Duryodhana are mentioned in Mahabharata, one princess of Kashi and another was princess of Kalinga. Kashi’s Princess was Chief wife of Duryodhana.
When Duryodhana went to the Swayamvara of the princess of Kalinga, she surpassed him as she wasn't interested in marrying him. Then he forcibly took her and Karna fought with the Kings present there and Duryodhana successfully took Kalinga princess away and brought her to Hastinapur. Due to Bhishma, no one dared to raise a voice against forcefully taking the Princess away. This Princess is called Bhanumati in the later versions but her original name is not mentioned in Mahabharata.
In Pampa Bharat and Villi Bharatham, an episode with karna and Bhanumati is mentioned. They were playing Dice and Karna was winning, when she saw Duryodhana entering the chamber, she got up to greet him but karna thinking she was scared and leaving the game, he grabbed her to make her sit and her pearl string broke. When Karna saw him, he was scared that Duryodhana would misunderstand their closeness but Duryodhana was perfectly nonchalant and said should he pick up the pearls or string them as well? The reply made them embarassed and Karna was overwhelmed how secure and trustful Duryodhana was towards him and Bhanumati. This story is not in Vyas Mahabharata.