Kusha , Champika and their daughter Hema
Kusha, the eldest son of Shri Ram and Mata Sita was married to Princess Champika, daughter of Maharaja Bhurikirti. Rishi Agastya after their marriage prophesized to Shri Ram that Champika won't be having any sons but daughters and when Shri Ram had left for Vaikuntha, Kusha would get a second wife named Kumudvati and get sons.
Kusha and Champika started their marital life and they had nine daughters together. Once Shri Ram organised a grand Swayamvara for Hema, beautiful and illustrious daughter of Kusha and Champika. Many Kings were invited in the Swayamvara along with Prince Chitrangad of Avanti.
Chitrangada fell in love with beautiful and illustratious Hema and wished to marry her. He hypnotized everyone in the Swayamvara while Shri Ram and other elders were away and took Hema on his chariot and left but he didn't go to Avanti and stopped midway as he considered it wrong to take her away like this. But it was too late, the royal house found it insulting and Lava and others attacked him in which Lava got unconsious. Then Kusha came and defeated Chitrangad and his father Ugrabahu and took them to Shri Ram. Shri Ram forgave them due to friendly relationship with Avanti and the good behaviour of the father and son in the past. It's not properly written but it's hinted that Hema was married off to Chitrangad as usually happened in such situations.
Shri Ram gave Kusha his famous golden arm- bracelet after this victory which was originally gifted to him by Rishi Agastya and years later this very bracelet became the reason of the union of Kusha and his love Kumudvati and the birth of meritorious, handsome and intelligent Atithi, the scion of Raghu and worthy grandson of Shri Ram.
Ananda Ramayana is considered a late source although it's writer is called Maharishi Valmiki. The source mentions history of sons of Lord Ram and his siblings.
Source- Ananda Ramayana