Complex sentence: Since Hardy was always highly critical of organized religion, as Emma become more and more religious, their differing views led to a great deal of tension in their marriage, and this tension was a big factor that led to their increased alienation from one another.
Split into simpler sentences: Since Hardy was always highly critical of organized religion, as Emma become more and more religious, their differing views led to a great deal of tension in their marriage. This was a big factor that led to their increased alienation from one another.