Complex sentence: The marriage was unhappy, often violent, stressed by lack of money and with several separations, but it was during the marriage that Comte wrote his masterwork, the six volume "Cours de Philosophie Positive" ("Course in Positive Philosophy").
Split into simpler sentences: The marriage was unhappy, often violent, stressed by lack of money and with several separations. But it was during the marriage that Comte wrote his masterwork, the six volume "Cours de Philosophie Positive" ("Course in Positive Philosophy").