Yamuna is said to have been the 4th wife of Krishna.
Krishna also married Rukmini, the princess of Vidarbha, by abducting her from her wedding on her request.
According to Bhagavata Purana, Krishna married with 16,108 wives of which eight were chief—including Rukmini, Satyabhama, Jambavati.
Rukmini, Satyabhama, Jambavati, Kalindi, Mitravrinda, Nagnajiti, Bhadra and Lakshana were the 8 principal wives in this order.
He loved Rukmini the most and she was His 1st wife, His main consort - the Patrani. As the incarnation of the enlightened Lakshmi, Rukmini bore all the qualities of a divine consort in human form.
Rukmini was the daughter of Bhishmaka, king of Vidarbha, who had decided to marry her off to a prince named Shishupala from... the kingdom of Chedi and was against her marrying Krishna.
Rukmini having fallen deeply in love with Krishna sent a message to Him to come and rescue her. Krishna abducted Rukmini from the wedding ceremony and married her in Dwaraka.
