As per Valmiki Ramayana, when Ravana visited Swarga loka, he saw the celebrated Apsara Rambha there and was immediately gripped by lust. Unable to check his emotions, he held Rambha. Shocked by his behavior, Rambha reminded him that he is equivalent to his father-in-law as she was tied up with Nalkuber, son of Ravana’s elder brother Kuber. But blindfolded by desire, Ravana ignored all her plea and seduced her by forcing himself on her. When Nalkuber came to know about this he cursed Ravana. The curse was : “If you seduce a women without her consent hereafter, your head will be blown in 100 pieces.”
Once Ravana was travelling by his Pushpak Vimana. He came across a beautiful woman. She was meditating to please Lord Vishnu to have him as her husband. Ravana approached her and pulled her by her hairs. Upon such humiliation, Tapaswini left her body and cursed Ravana that one woman will be the cause of his demise.
Ravana didn’t even spare the elder sister of his wife Mandodari called Maya. Maya’s husband Shambhar was king of Vaijyantpur. Ravana tried to woo his wife Maya. When Shambhar came to know about this, he held him captive in his prison. Meanwhile, King Dashrath invaded Shambhar’s territory. During the war Shambhar lost his life. When Maya decided to get Sati, Ravana asked her to come with him. She cursed him and said, “Lust, which has turned you blind, will prove to be the single cause of your fall.”
The most famous of all the women in Ravana’s life, Sita was the sole cause of his demise. Had there been no Sita, nobody ever even knew about Ravana. The whole of Ramayana conflict is an aftermath of Ravana’s abduction of Sita. Ravana had captured her, disguised as an ascetic, near Panchwati and kept her captive in Lanka for two years. Although due to Rambha’s curse he never tried to led a finger on her. He had proposed marriage to Sita, to which she declined, saying, “like Sun and rays Rama and Sita are also inseparable.” There goes one more theory which says that Sita was actually Ravana’s daughter
Ravana was married to Mandodiri, who was daughter of Maydanava. She was said to be daughter of an Apsara called Hema. Some say that her native place was in Madnsaur of Madhya Pradesh, some other say it is in Mandor, near Jodhpur in Rajasthan. Ravana and Mandodiri had a son called Meghanada, who after defeating Indra, came to be known as Indrajeet. Mahodar, Prahast, Virupaksha, Bhikam Veer were other sons of Ravana, all killed in the battle of Ramayana.