Using General Social Survey data, I calculated the relationship between attending religious services and cheating on your spouse for people of various religions. (The sample is whites only, except in the case of Hindus).
Logistic Regression Coefficients
No religion .04
*p < .05
More attendance of religious services predicts remaining faithful for the Abrahamic religions only, and the effect for Muslims is not statistically significant. Buddhists, Hindus, and people with no religion who are active in religious activities are just as likely to cheat as those who never attend. Being a religious Jew is the strongest predictor of fidelity.