Why did Krishna had more than 16,000 wives?

We understand from the Srimad-Bhagavatam, that when Krishna was present on this earth He had 16,108 wives; however, because Krishna sometimes appears like an ordinary man, people sometimes cannot believe or understand His activities. They wonder, “How can God become an ordinary person like us?” But although Krishna sometimes plays like an ordinary person, in fact He is not ordinary, and whenever necessary He displays the powers of God. When sixteen thousand girls were kidnapped by the demon Bhaumasura, they prayed to Krishna, and therefore Krishna went to the demon’s palace, killed the demon, and delivered all the girls. But according to the strict Vedic system, if an unmarried girl leaves her home even for one night, no one will marry her. Therefore when Krishna told the girls, “Now you can safely return to your fathers’ homes,” they replied, “Sir, if we return to the homes of our fathers, what will be our fate? No one will marry us, because this man kidnapped us”. “Then what do you want?” Krishna asked. The girls replied, “We want You to become our husband”. And Krishna is so kind that He immediately said yes and accepted them. Now, when Krishna brought the girls back home to His capital city, it is not that each of the sixteen thousand wives had to wait sixteen thousand nights to meet Krishna. Rather, Krishna expanded Himself into sixteen thousand forms, constructed sixteen thousand palaces, and lived in each palace with each wife.

Although this is described in Srimad-Bhagavatam, rascals cannot understand this. Instead they criticize Krishna. “He was very lusty,” they say. “He married sixteen thousand wives”. But even if He is lusty, He is unlimitedly lusty. God is unlimited. Why sixteen thousand? He could marry sixteen million and still not reach the limits of His perfection. That is Krishna. We cannot accuse Krishna of being lusty or sensuous. No. There are so many devotees of Krishna, and Krishna shows favor to all of them. Some ask Krishna to become their husband, some ask Krishna to become their friend, some ask Krishna to become their son, and some ask Krishna to become their playmate. In this way, there are millions and trillions of devotees all over the universe, and Krishna has to satisfy them all. He does not need any help from these devotees, but because they want to serve Him in a particular way, the Lord reciprocates. These sixteen thousand devotees wanted Krishna as their husband, and therefore Krishna agreed.

Source : A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “Teachings of Queen Kunti”, Page 90 & 91
A.C. Bhaktivedanta Swami Prabhupada (2014 edition), “The Science of Self-Realization”, Page 21