S4·E24 The End of the Innocence (2)

After catching Dharma innocently hanging out with her old college tutor---and failed suitor---Charlie, an enraged Greg moves out. Then the misunderstanding turns into a crisis as they both get caught up in the planning of their mutual friends' impending wedding, compelling Greg to seriously reevaluate his own crazy marriage. But when he finally sees the light, it may be too late.