Complex sentence: Carly had a one night stand with a man she met in a bar soon after arriving in town, whom she later learned was Michael "Mike" Kasnoff, Rosanna's fiancé.
Split into simpler sentences: Carly had a one night stand with a man she met in a bar soon after arriving in town. Carly later learned that man was Michael "Mike" Kasnoff, Rosanna's fiancé.