HOPE THIS HELPS !!
If you have read the story, it must be quite evident to you that Nnaemeka and Nene consider marriage a private affair.
When Nnaemeka told his father that he did not love Ugoye Nweke, he showed that his marriage his rightly his decision, and he has the right to marry his beloved(Nene)
I mean it is impossible for me to marry Nweke's daughter
On the other hand, Okeke, Nnaemeka's father, found that marriage was not by choice but by chance. If a particular is from the Ibo tribe, then she was eligible to marry.(Seems like a contest, isn't it!!)
Nnaemeka : I dont love her
Okeke : Nobody said you did, why should you?