Among the greatest dangers to the freedom of thought is not the bonfires of tyrants, nor the sharp strokes of the censors pen, but the gentle state of matrimony. If a spouse cares anything at all for their beloved they will always do their utmost to spare hurt feelings.
This is an expected and laudable thing to do in most marriages. No one would remain long with someone who continually appeared at odds with them in the deepest sense, that is, in what they believe. But at a certain point this may become less an inconvenience than a neglect of the greater good.
It has for this reason become a cliche that philosophers don't marry. Socrates was the perennial example of the hen-pecked house-mate who's wife, concerned merely with the day to day concerns of this life, was unable to understand those of her husband's for the life of the mind.
I can think of few better examples of this in modern times than that of Charles and Emma Darwin. Their's was a truly deep and respectful love that continued unbroken through the whole of their marriage. However, late in life when Darwin had dispensed with the religion of his childhood, his wife remained a devout Christian. It was for this reason perhaps more than any other that he delayed the publication of his most famous work, On the Origin of Species, until professional pressures at last forced it to the press.
"When I am with you" she writes before their marriage. "I think all melancholy thoughts keep out of my head but since you are gone some sad ones have forced themselves in, of fear that our opinions on the most important subject should differ widely. My reason tells me that honest & conscientious doubts cannot be a sin, but I feel it would be a painful void between us. I thank you from my heart for your openness with me & I should dread the feeling that you were concealing your opinions from the fear of giving me pain."
Such gentle words can do more to bring a man to rethink the truth then all the lashings of the scourge and heckles of the crowd combined.
In the end, Darwin of course published and set a conversation going between faith and science that has yet to have an end. It is a testament to the strength of their feeling for one another that the ensuing controversies did not dim that love, however much it may have tested it.
Their example is both as beautiful as it is, sadly, rare.