She is going to tell them herself tonight to get whatever punishment they mete out, but there is no way they will be involved in our marriage.
Several already said it, but going to the elders will just muck up the waters even more. Yes, it is "loose conduct" as someone already mentioned, but does not constitute "pornia", thus I do not think it qualifies as grounds for scriptural divorce. If you both agree to work things out, she would likely receive "private" reproof. If it appears to be leaning to a breakup, then probably "public" reproof. Read her Psalms 32:5 where King David said he confessed his sin to Jehovah [not the priests]. Read the section in the Reasoning Book about "Confession". From that she can conclude that she need not speak with the elders [if there is any chance that she can be convinced]. I would also stress that YOU do not want THOSE MEN knowing YOUR private life, and as Family Head, since there was NO "pornia", she is NOT to reveal confidential information about your personal life to those outside your family.
Did she cheat? Damn right! She cheated with her heart even if not with her [genitals]. With a woman, her heart is always involved first. A man can get drunk, get propositioned, unzip & whip it out for a quickie, and walk away without his heart ever being involved in it all. [Men are all @$$holes.] Not so for a woman. That doesn't mean you can't fix things. It just means you both have to want to fix it.
Yes, she needs to quit that job. Frankly, I'd be surprised if the company did not have rules against such conduct, esp if either of them is in a higher position of authority than the other. Then the issue of sexual harrassment has to be factored into the scenario. Chances are they would let her quit and draw unemployment just to see the risk of a harrassment suit go away.
Finally, COUNSELING COUNSELING COUNSELING. (NOT from the Elders.) Go to someone professional. Lots of marriages survive an affair. Look at it as a warning sign to both of you that you were fortunate to get BEFORE it went beyond the point that it did. The fact that she did not go further is likely based on the JW "rules". She was able to compromise to that point because it is a different level of transgression. Lots of youth in my day rationalized all kinds of petting, but stopped before "penetration" as that was the WT rule of the day.
Perhaps she has felt neglected by you (work, school, etc) and this guy may be a predator who sensed her feelings. Yes, there are men like that. It's Christmas Break so it's time for you to allow time to be more attentive. If you are both still in love, forgive. People make mistakes.
Did I say COUNSELING?
DOC