It’s not really a secret that Jay Cutler’s douchebaggery is only rivaled by his groundless sense of self entitlement. (And I’m a Bears fan.) According to Hollywood Life, that is what ultimately led to the Jay Cutler Kristin Cavallari break up.
Jay is the one who broke up with Kristin, but he is also the one who is toxic in their relationship. The current (and most believable) rumor is that they constantly had explosive arguments. Neighbors could hear them yelling and fighting.