M.G.L. 208 s 34 provides a list of factors for the court to consider in dividing marital property and/or assigning alimony awards. One of these factors is "the conduct of the parties during the marriage." Quite often this is the factor that clients want to talk about the most, but is the least important factor to the court. Although adultery and other offensive behavior may have led to the divorce, the Judges are used to seeing this behavior in so many cases that they become jaded to it and prefer to focus on the financial factors most of the time.
This means that bad conduct which affects the finances (such as spending money on an extra-marital affair or gambling) will be taken into account, but often bad conduct which does not affect the finances will not. However, this does not mean that non-financial bad conduct has no effect at all, and sometimes if it is egregious enough the court may consider its effect on the marriage itself.
Especially if the conduct is significant as in the case of Wolcott v. Wolcott. In that case, the court awarded the Husband approximately 90% of the martial estate, primarily due to the Wife's extremely bad conduct. Because of attempts that the Wife made to find someone in the "mafia" to make her husband "disappear", a jury convicted the wife of solicitation to commit murder, and she served three months in the house of correction before being released on parole.
Although this is obviously an extreme example, the Court indicated that consideration of much less egregious conduct under § 34 has been approved. The Court further indicated that conduct could be considered which harmed the martial estate OR the marriage itself.