Internet communication can mean lots of different things today. We have webcams and photos which are often used and exchanged as a part of the “relationship” that people create via the internet. It is hard to know precisely what the questioner is asking here, but for the sake of simplicity, I will assume the question at hand involves only written communication.
As far as I know, adultery is interpreted to be a physical act in Halacha (Jewish law), though the law sets up parameters that guide us in making certain assumptions about impropriety. Traditionally, men and women who are not family and are not married are not permitted to be in a room alone together, as it is assumed that if they are, there was some form of inappropriate physical interaction. In other words, the boundaries we erect to guard against adultery reflect a sense that temptation is very difficult to resist. I would apply the same assumptions toward what mental health professionals call “emotional affairs.”
Dr. Gail Saltz, Associate Professor of Psychiatry at The New York Presbyterian Hospital Weill-Cornell School of Medicine, teaches that denial is a hallmark of emotional affairs. People convince themselves that since there is not sex involved, there is no betrayal of one’s spouse. She writes, “Many people convince themselves that as long as there's no sex, it's not an affair. But it is. An affair really has to do with secrecy, deception of the partner and betrayal. It also has to do with the amount of emotional energy that you put into the other person and are no longer giving your partner. Most people are more disturbed by the breaking of trust than by the sex—it's what's most difficult to recover from when a partner has an affair." When we have a relationship with another person via the internet, we may invest the same type of emotional energy in it and be just as deceptive of our partners as we would be if that relationship were face to face. In other words, I would not distinguish between emotional affairs conducted through the internet or in person. They are both affairs. Your question is whether or not this violates the commitment one makes to his/her spouse.
In Genesis, the Torah teaches that Adam and Eve were created for one another. The text states, “for it is not good for a person to be alone.” We need intimate relationships in our lives in order to fulfill a deeply important need for companionship. The institution of marriage is meant to fill this need. In your question, you ask about the violation of one’s vows. In Judaism, we don’t get married through vows as one does in other religious traditions. We are married through the recitation of blessings, and one of them says, “Grant perfect joy to these loving companions, as You did for the first man and woman in the Garden of Eden.” We are re’im ha’ahuvim, loving companions. In my opinion, developing a relationship with another person that fulfills a deep need for emotional intimacy does violence to the commitment reflected in this blessing. You can’t be a loving companion to someone from whom you are hiding another relationship.
My recommendation is to use transparency as a measuring tool for appropriateness. If you are willing to share the dynamic of the relationship that you are developing through the internet with your partner, and s/he is comfortable with it, it seems that the relationship is appropriate. If you are hiding the frequency of your communications from your partner or the details of your relationship, it is an egregious violation of the trust you are responsible to create with your partner.
After Eve is created and brought to Adam, the Chumash tells us “Therefore a man shall leave his mother and father and cleave unto his wife, and they shall be as one flesh”. The Ramban (Nachmanedies) explains that “cleave unto his wife and they shall be as one flesh” implies that the relationship between husband and wife, though it is normally not a blood relationship, should be a person’s most intimate and strongest relationship. Halachah follows this relational approach by telling us that should there be a conflict between honoring a spouse or honoring a parent, the honor due to a spouse must come first. I would add that as a therapist I have discovered that the relationship between a spouse and in-laws have much more to do with how secure a person feels about the spousal relationship than the direct in-law relationship.
All this being said it is quite clear that any intimate internet relationship with other than one’s spouse is viewed by Judaism as inappropriate and damaging to the marriage. Though the Bible permits polygamy, it clearly prefers monogamy, with polygamy taking place among our forefathers for progeny reasons (Abraham and Jacob) or because of deception (Jacobs’s marriage to Leah and Rachel). Intimacy excludes all others, or else it is not intimacy. I have counseled, as both rabbi and therapist, situations not just of physical adultery, but even more commonly emotional adultery.
Therefore, one crosses the line and violates one’s spousal vows when one has developed an intimacy with one’s internet friend which should be reserved for one’s spouse. So how does one know one has gone beyond the Pale. First, I believe if one’s spouse is uncomfortable with the internet relationship and either openly objects or signals in other ways objection, one has damaged one’s marital intimacy and needs to end the internet relationship. Protestations that one’s spouse is too sensitive reflects a lack of empathy on the part of the husband/wife and is no excuse for continuing the internet relationship. Second, if one finds oneself preferring the intimate internet company over one’s spouse (especially if one fantasizes sexually about that company), one has overstepped one’s boundaries and needs to work harder on one’s marriage. Remember, the internet company doesn’t live with you, hear you snoring or watch you run to the bathroom with an upset stomach. The internet relationship is a fantasy. One must never allow the internet to damage one’s very real marital relationship.
In today’s era of instantaneous and anonymous Internet communication, any online liaison has potential danger. If this is true, how much the more so are those communications that, as you put it, ‘cross the line!’
It is an unfortunate reality that we sometimes do not truly know with whom we are communicating, or whether their photograph is authentic, or whether their biographical material is valid, or whether their ‘life story’ is genuine. In my opinion, no one whom you meet online ought to be trusted implicitly, and any communication in which you engage should be done with an eye toward preserving your privacy and your integrity. These communications should be held at arms length.
The question suggests a situation where you feel that communication has, indeed, crossed the line to a dubious area. If so, the Seventh Commandment should certainly inform your actions. The sacred obligation of “Do not commit adultery”, in my humble opinion, should refer, in addition to sexual infidelity, to emotional betrayal as well. When one gives one’s heart to someone other than his/her spouse – regardless of whether there has been sexual intimacy – that is an act of adultery. And if the liaison is ‘to allay only some feeling of loneliness’, the perpetrator should look within him/herself to determine the reason for that feeling, and then determine a healthier course of action than one of emotional betrayal.
To answer the question directly, the crossing of the line exists when you express an emotional or sexual desire toward that other person, when you confide in that person issues that concern you and your spouse (that you have not shared with your partner), when you plan for an actual get-together, or even sharing (sexual) fantasies with that other person. These are all matters that should remain between partners or spouses, and any violation of these spousal or partnership ties would constitute “crossing the line.”