Lord Krishna has many wifes excluding Radha or Rukumini (i assume both are same), this question says about what happens to Radha after Lord Krishna. but What happened to other wives of Lord Krishna after he left?
Only very few scholars think that Radha and Rukmani are same. Most of the scriptures say that they were different.
What happened to Rukmiṇī and other major wives of lord Krishna after he left?
rāma-patnyaś ca tad-deham
pradyumnādīn hareḥ snuṣāḥ
kṛṣṇa-patnyo ’viśann agniṁ
The wives of Lord Balarāma also entered the fire and embraced His body, and Vasudeva’s wives entered his fire and embraced his body. The daughters-in-law of Lord Hari entered the funeral fires of their respective husbands, headed by Pradyumna. And Rukmiṇī and the other wives of Lord Kṛṣṇa — whose hearts were completely absorbed in Him — entered His fire.
Other survivors of the Yadu dynasty — the women, children and old men
Arjuna took the survivors of the Yadu dynasty — the women, children and old men — to Indraprastha. He installed Vajra (the son of Aniruddha) as ruler of the Yadus.
Related chapter of Śrīmad-Bhāgavatam (Bhāgavata Purāṇa) : SB 11.31: The Disappearance of Lord Śrī Kṛṣṇa