Occasionally I will get a couple in my office that have a particular problem. I also happened to get an email about this problem so thought I would address it with a video. Let me briefly describe it. You or your partner go to work every week. During this time at work you start to become friends with a variety of people. You start connecting a bit more at work with someone of the opposite sex. You think, It's harmless of course, because it's at work. Work stays at work and home stays at home.
You continue to share experiences at work and slowly this work relationship begins to encroach into your home life. When your partner makes comments and questions you, defensiveness sets in. Then you have arguments about control and affairs.
You may say "what's the harm in texting or having close relationships with the opposite sex while you're in a relationship?"
Let's be clear, ultimately you get to do what you want as an adult. You get to make your own choices wherever you want...at work...in public...in your relationships. What I have found is that one of the most cliche things that break up long-term relationships is not having clear and appropriate boundaries with your work relationships.