For some men, the stronger their desire, the more difficult it is for them to act. They are hampered by mistrust of themselves, daunted by the fear of giving offence; besides, deep feelings of affection are like respectable women; they are afraid of being found out and they go through life with downcast eyes.

Gustave Flaubert (1821-1880) French writer, novelist

Sentimental Education, Part 2, ch. 3 (1869)
    (Source)

Elsewhere as Book 2, ch. 16.