I was on a hike with another couple and the husband asked me to identify the number one thing I would tell people to keep their marriages strong. I'm not usually asked to reduce marital tips down to one dimension, but I was intrigued by the challenge. I thought for a minute and realized I had a definite answer, informed by the cases I have had over the last 5 years.

"I would say," I replied, "To realize that when you are texting someone, you are in essence entering a private room with that person." I'm expanding on the image here. The room has no windows. The social response is in real time, so it is as if you are right next to the person having an actual conversation. If you text daily, you are entering that room daily. If you text on and off all day long, you are in that room most of the day. Everyday.

I see a lot of infidelity cases. One hundred percent of them in the last few years have all developed through texting. In most cases, a romantic interest did not precede the texting relationship. Most of them started in a benign way between co-workers, church members working together on projects, neighbors and best friends of the couple. Here's the typical developmental course (IMHO):

1. Begin texting to communicate practical information.

2. Increase frequency of texting, still to communicate practical information.

3. Add a joke to your text, making it more conversational in nature.

4. Get a response to your joke, and continue the playful banter.

5. Feel a positive chemical boost after a text exchange.

6. Find yourself checking your phone to see if the person texted.

7. Realize that you are starting to look forward to getting texts from that person.

8. Tell yourself that since you aren't seeing that person face-to-face, you are fine and not being disloyal to your spouse.

9. Increase casual and playful texting.

10. Shift from playful banter to deeper emotional disclosures.

11. Experience an increase in the euphoric chemical boost.

12. Find yourself hiding your phone from your spouse, because you don't want the texts to be "misinterpreted." (ALERT: Tipping Point)

13. Continue to tell yourself that nothing is going to happen, because you still aren't in this person's physical presence, so you are still in control.

14. Realize you have an emotional yearning for this individual.

15. As you increase the need to hide your texts, begin to see your spouse as the enemy.

16. Find yourself disconnecting from your spouse to find a place to text this person more often and privately.

17. Hide more.

18. Declare your deepest feelings and yearnings for this person and plan to meet in a private location.

19. Engage in physical affection.

20. Bam!

21. Feel as if you have "fallen," in love with this person and want him/her more than your spouse.

22. Tell yourself this is your true love connection ... otherwise you wouldn't have "fallen," in love, and you wouldn't have these feelings.

23. See your spouse as the one thing standing between you and true love and happiness.

24. Destabilize your family.

25. Make an appointment with me.

This may sound harsh to some readers ... definitely to those who see themselves somewhere on this continuum. I'm not changing my story. If you would not repeatedly enter a private room with someone without a window where someone can see in, frequently enough that you start to share feelings with someone that you wouldn't share with your spouse, don't do it on a cell phone.

Here's one more thing that should not surprise you: If your texting partner is an old boyfriend or girlfriend, you can expect to immediately resurrect the same emotions you felt when you were dating that person. You will exaggerate all the good memories you had and minimize the negative memories you had from that relationship. That's not unique. Your texting affair is not unique, and the effect is as if you are on drugs. I've written this before and I stand by it.

Lastly, realize that no matter how great you think your marriage is, this can happen to you. It is the failure to be watchful and set boundaries that gets people into trouble. If you think you could never end up having an affair, you're kidding yourself.

Editor's note: This article was originally published on Lori Cluff Schade's website. It has been republished here with permission.