Neminath Bhagwan (Arishtanemi) had no wife in his final birth as a Tirthankara. He is described as a celibate Arihant who renounced marriage before his renunciation, so his last life had zero wives.

In his earlier births, he did have wives, the most famous being Rajul (Rajimati) in several lives, with accounts saying they lived as husband and wife for eight consecutive births before renunciation and liberation. So the number depends on which birth you refer to; in his final life there were none. You can read more about his past life with Rajul here and about his final birth here .