Krishna is the avtar of vishnu. He is said to have married many women. His love was radha.
His wives were – rukmini, satyabhama, jamvanti,lakshmana, rohini, mitravrinda, Nagnajiti, kalindi
Apart from these, he married 16,000 women who were captives of narkasur after killing him
Radha, Rukmini, Satyabhama are incarnation of Nil lakshmi, Sri lakshmi, Bhu Lakshmi
I think the other 6 wives were also ansh of lakshmi
Regarding 16,000 wives who were considered as junior wives, I am not sure but I read about them that they were rishis in past who wanted to be a part of his incarnation on earth
According to some stories, they represent the 16 arts of Krishna
Some say they were apsaras
Regarding gopis, I read in ram avtar when he was searching for Sita, the rishis and other creatures wanted to comfort him as he was loyal to sita so he gave to be born as gopis and comfort him in his next birth as Krishna