Adultery used to be seen so negatively that it was defined as one of the few faults for which a divorce would be granted. Today, you do not need to prove that your spouse did anything wrong to ask for a divorce, even though you can list adultery as a cause.
There are laws against adultery because marriages are meant to be monogamous by law. In a fault-based divorce, you can select to place adultery as a factor and use it as a negotiating tactic in your case. Adultery can affect your divorce proceedings.
How? Judges have the right to equitably divide your marital assets in equitable distribution states like Virginia. The process itself is based on each person's need, but it's also based on what's fair. If the adultery led to tangible economic consequences, it's more likely to affect the case. For example, if a spouse was spending a paycheck on another woman, then the spouse who had to make up expenses and go into debt to support the home might be able to prove that adultery played a role in an economic sense.
It's unlikely that a case of adultery would lead to criminal charges or anything else outside the divorce, but showing that one spouse is at fault can help sway a judge to look at you more favorably. Your attorney can help you put together the information you need to show that your spouse was adulterous and that it has affected you financially. You've been through a lot, and you deserve to be fairly compensation for your struggles.
Source: FindLaw, "Punishing Adultery in Virginia A Cheating Husband's Guilty Plea Is A Reminder Of the Continued Relevance of Adultery Statutes," Joanna Grossman, accessed June 16, 2017