In the poem marriage is a private affair, why does nnaemekas father at first resist meeting his grandchildren

He refused to meet his grandchildren for he is of the opinion that his son, Nnaemeka had gone against his will in marrying a girl from another tribe.

Explanation:

Chinua Achebe's short story "Marriage Is A Private Affair" tells the story of the protagonist Nnaemeka's conflict with his father after he decided to refuse his father's choice of his wife and instead married a woman from another tribe.

His father had first suggested a woman from the same tribe to be his wife but he refused, insisting that he didn't love her and he's already engaged to another girl from the Nene tribe. Even after years of marriage couldn't bring the father to forgive his son. But the letter sent by Nene to him at the end of the story, telling him of how the children wanted to meet their grandfather, was enough to stop his hard heart from being arrogant as usual. He did not want to deny the children anymore, questioning in his mind "How could he shut his door against them?". Thus, the refusal of Nnaemeka's father to meet the children was his initial anger and resentment of his son's refusal to marry a girl of his choosing and instead marrying someone from another tribe.