He entered the hospital, complaining that Ms. Middleton was insensitive. “I was ill and didn’t think she cared enough,” he said. “After texting each other, she came back sobbing, telling me that she was a great girl, and that I won’t ever meet anyone like her again.

“That defining moment,” he continued, “was the first time I knew I would someday make her my wife.”

But there were challenges to overcome. Mr. Ogike still embraced certain aspects of his Nigerian culture, like not wrapping Christmas gifts and playing down birthdays. (Ms. Middleton loves birthdays.) He also speaks in the native Igbo language to his father, a retired college professor, and other family members who live in California. (“I felt left out,” she said.) And he favors traditional Nigerian foods like goat meat, chewy chicken, rice and soups. (Ms. Middleton wasn’t a fan.)

Ms. Middleton also noted that the Nigerian culture favored traditional roles for men and women. “Nigerian men expect to lead, with the woman being a caretaker,” she said. “My mom and dad both worked, and my dad did child-rearing, too. Ike’s family was not like that.”

But they learned to understand each other, often resolving any conflicts the same day.

“Ike is an uneasy guy who feels at home with Brittney because she is down-to-earth and humble,” said Obi Dukes, a groomsman. “He was never that close to any girl before. It’s a beautiful thing to watch them together.”

In August 2015, Ms. Middleton complained of “feeling funny” and soon learned that she was pregnant.

“This was a total shock to me because it was so soon, and I thought Brittney was on birth control,” Mr. Ogike said. “While we had talked about having three children after we married, I never wanted a child out of wedlock.”