ŚB 1.13.16

Both Mahārāja Yudhiṣṭhira and Arjuna were unhappy from the beginning of the Battle of Kurukṣetra, but even though they were unwilling to kill their own men in the fight, it had to be done as a matter of duty, for it was planned by the supreme will of Lord Śrī Kṛṣṇa. After the battle, Mahārāja Yudhiṣṭhira was unhappy over such mass killings. Practically there was none to continue the Kuru dynasty after them, the Pāṇḍavas. The only remaining hope was the child in the womb of his daughter-in-law, Uttarā, and he was also attacked by Aśvatthāmā, but by the grace of the Lord the child was saved. So after the settlement of all disturbing conditions and reestablishment of the peaceful order of the state, and after seeing the surviving child, Parīkṣit, well satisfied, Mahārāja Yudhiṣṭhira felt some relief as a human being, although he had very little attraction for material happiness, which is always illusory and temporary.