As far as we know, Gaara has never married or had any children, which proved to be a source of fear for the people of Sunakagure. This was mostly because Temari had married Shikamaru from Konoha.
Gaara won’t marry anyone at the end of Naruto. If you see Gaara at all series of Naruto he doesn’t have any interest for any of girls who appears in Nuruto. Even for the fact that, Sakura, Ino, Hinata and Temari had interest on other guys like Sasuke, Sai, Naruto and Shikamaru.
In Boruto: Naruto the Movie, Gaara has adopted a child named Shinki.