Death of Ravana

Ravana, shocked at the death of his son, came to fight. He saw Vibhishana and shot an arrow to kill him. Lakshmana cut that off. Angry, Ravana took a might spear and hurled that towards Lakshmana. Lakshmana fell. Hanumana then fetched the medicine and brought Lakshmana back to life.
Ravana then came back to fight. Indra sent a chariot for Rama.
Rama cut off the heads of Ravana and new heads emerged.
Vibhishana said Ravana could be killed by only one specific arrow that had been hidden by Mandodari.
In disguise, Hanumana tricked Mandodari to tell him where the weapon was and brought that to Rama.
Using that, Rama killed Ravana.
When Sita came to Rama, Rama said to her - You stayed ten months in the palace of a demon and I will not accept you.
Sita asked Lakshmana to light a pyre and jumped into that.
Agni came out and handed Sita over to Rama.
Rama then crowned Vibhishana the king of Lanka and then returned to Ayodhya.
Ravana and Kumbhakarna were none other than Jay and Vijay who were killed by Rama.
Later Jay and Vijay were born as Shishupala and Dantavakra. Shishupala tried to stop your sacrifice and was killed by Krishna. Later Krishna killed Dantravakra also.
Thus in three births, Jay and Vijaya were killed by incarnations of Vishnu.

What is your grief in front of Rama's. All will be well soon. Draupadi is pure like Savitri and should not be doubted.