The following passage says that Saraswati appeared in person before the Matinara and chose him for husband. The passage was narrated by Vaisampayana to Janamejaya
And of her was born a son named Arihan. And Arihan took to wife Sudeva, the princess of Anga, and upon her he begat a son named Riksha. And Riksha married Jwala, the daughter of Takshaka, and he begat upon her a son of the name of Matinara, who performed on the bank of Saraswati the twelve years' sacrifice said to be so efficacious. On conclusion of the sacrifice, Saraswati appeared in person before the king and chose him for husband. And he begat upon her a son named Tansu. Here occurs a sloka descriptive of Tansu's descendants.
"Tansu was born of Saraswati by Matinara. And Tansu himself begat a son named Ilina on his wife, the princess Kalingi.
Note: Answers says that Saraswati, the goddess associated with the river Saraswati is either a partial or full incarnation of the wife of Brahma. If full incarnation, then both will be the same. Else, who married to Matinara? Full or partial incarnation of Saraswati?