Although infidelity is frequently portrayed in relationship theories as a negative development in a couple's lives, it is still unclear whether relationship issues arise as a result of infidelity, before it occurs, or as a result of both. Infidelity was shown to be preceded (but not followed) by a progressive decline in relationship functioning in both the perpetrators and the victims in studies of dyadic panel data of adults in Germany encompassing roughly 1,000 infidelity incidents. With the exception of unfaithful women and people with lower initial relationship commitment, there was little evidence of rebound effects following infidelity; instead, these people returned to their pre-event levels of wellbeing or even surpassed them, lending support to the expectancy violation theory (vs. the investment model of infidelity).
