By Jeff Herring,Knight Ridder Newspapers

“But we are just friends” are five of the most dangerous words for a marriage. The majority of extra-marital affairs begin as “just friends.”

Gary Rosberg of America’s Family Coaches states that there are at least 19 stages a person will pass through on the way to physically consummating an extra marital affair. There are at least two important notions that we can lift from Rosberg’s statement:

• At each and every one of the 19 steps, you have a clear choice between going further down or stopping the process.

• An affair becomes adultery long before the physical act. In fact, emotional affairs can be stronger and more difficult to get out of than physical affairs.

The late Shirly Glass was a pioneer in the area of emotional affairs. In her 2003 book “NOT Just Friends: Protect your relationship from infidelity and heal the trauma of betrayal,” Glass identifies three red flags that indicate that you have progressed from a safe friendship to a romantic emotional affair:

1) You feel closer to your friend than you do your spouse.

2) Keeping secrets. You no longer feel comfortable telling your spouse about this person. You begin to cover up so as not to be found out.

3) An increasing sexual tension. You admit your attraction for each other, but promise that you can never act on it. You fantasize what it would be like to be with this person.

One of the most overlooked and dangerous facts about emotional affairs is that we are all vulnerable.

How to protect yourself and your relationship:

• Keep clear boundaries. A boundary is simply what kids mean when they say “don’t go there.”

• Avoid being alone with and/or emotionally close to someone to whom you are attracted.

• Talk often about your spouse. “Spouse bashing” does not count. Talk about what you have done lately and what you are looking forward to with your spouse.

• If you are going to talk about emotional issues in your marriage, make sure you are talking to your spouse, a trusted friend who is on the side of you and your marriage, or a professional who is on the side of your marriage.

• Be especially careful at work. Do not make a habit of taking private lunches or breaks with the same person over and over.

In closing, remember that we are all vulnerable, watch for the warning signs, and protect yourself and your marriage.

Jeff Herring, MS, LMFT, is a marriage and family therapist.