“In September of 1837, Darwin suffered palpitations of the heart, which would plague him throughout his life. Recuperating in his home town of Shrewsbury, he was introduced to his cousin, Emma Wedgewood, who mended his heart, and then won it. Charles Darwin and Emma Wedgewood fell in love, but ever a man of method, he drew up two lists. One called ‘Marry,’ one called ‘Not Marry,’ and he worked through the pros and cons. He concluded that ‘A constant companion and a friend in old age’ outweighed ‘Less money for books’ and ‘The terrible loss of time.'”
–Melvyn Bragg, from “In Our Time: Darwin, Part 2” on BBC Radio 4
The Darwins had ten children.