Complex sentence: When Daniel warned Michelle of Ruth's strange antics, Michelle confronted Adam about his relationship with Ruth; in which she discovered he had been seeing her secretly and that Ruth had been stealing her possessions including her clothes for months.
Split into simpler sentences: When Daniel warned Michelle of Ruth's strange antics, Michelle confronted Adam about his relationship with Ruth. She discovered he had been seeing her secretly and that Ruth had been stealing her possessions including her clothes for months.