Perhaps there is no relationship in Charles Darwin´s life more saddening and heartening at the same time as that of his wife, Emma Darwin. Simply put, they were unconditional soulmates. However, on "the most important issue" of religion and God, their disagreement was vast and wide.
The motive behind the original proposal is vague, as there was little to no courtship. Emma was entirely suprised when Charles showed up at her house one day to ask for her hand in marriage. The only person more suprised might have been Charles himself when she accepted on the spot. It was a marriage that began in timidiy, not in lust, passion, or some other sappy romantic story. One of the conversations that the couple did have on the subject was on religion and faith. Emma was a devout and pious Christian while Charles had some serious doubts. Ignoring his father´s advice about not disclosing this particular bit of information, he preceded to tell Emma of his doubts. While she disagreed with him and would continue to disagree for the rest of her life, she agreed to marry anyway.
As the marriage progressed, they fell more and more in love with each other. More than just being there for Charles when he suffered from his continual and mysterious illness, they were the emotional rocks of each other´s lives. When they were dealing with stress, grieving, or mouring, they could barely stand to be away from each other´s presence. Yet behind this seemingly perfect marriage, there was still that one lingering issue.
It manifested itself in a letter that Emma wrote to Charles during their engagement period. The jist of the letter wrote that Emma would be most sad indeed to not be sure that her and her husband´s souls belonged together in eternity. While Charles largely chose to ignore this issue with her, it definitely took great weight on his thought. In fact, on the very letter he wrote to her, "When I am dead, know that many times I have kissed and cryed over this." It was an issue that neither wanted to bring up but that neither could forget. In some almost inexplicable way, their greatest happiness was also the source of their greatest sadness.