When couples come to me for counseling, one of the first things we sometimes have to address is a genuine disagreement about whether one partner is having an affair. Not a physical one — an emotional one. And this particular disagreement can be especially charged, because one partner is saying "it's just a friendship" and the other is saying "it doesn't feel like just a friendship to me."

Here's what I want couples to understand: this is not simply a matter of competing opinions. It's not his word against hers. Relationships have real, definable characteristics — exclusivity, mutuality, emotional transparency — and those characteristics provide an actual framework for evaluating whether a friendship has moved into territory that violates them.

The Signs, According to Research

Dr. Shirley Glass, whose book Not "Just Friends" remains one of the most important works on the subject, outlines the signs that a friendship has become an emotional affair. Your friendship has likely crossed a line if:

  • You tell your friend more about your daily life than you tell your partner.
  • You discuss problems in your marriage with your friend instead of, or more than, with your partner.
  • You're not fully open with your partner about the extent of your connection with this person.
  • There are parts of your conversations you'd be uncomfortable if your partner heard.
  • You'd be uncomfortable if your partner saw a video of you two hanging out.
  • You're aware of sexual tension in the friendship, even if you don't plan to act on it.
  • You touch each other differently in private than in public — longer, more intimately.
  • You're in love with your friend.

If none of these apply, the friendship is almost certainly just a friendship. If three or more apply, something is developing. If most of them apply, you're in an emotional affair.

Walls and Windows

Glass uses the image of walls and windows to explain the dynamic. In a healthy relationship, you have a window open to your partner — transparency, emotional access, honest sharing. You maintain appropriate walls between yourself and people outside the relationship.

An emotional affair happens when that gets reversed: you start building walls between yourself and your partner, and opening windows to someone else. You're giving the outside person the emotional access that belongs to your partner.

This Can't Be a Matter of Opinion

If your partner is uncomfortable with your outside friendship, you don't get to simply tell them they're wrong and continue as before. Even if they've had jealousy issues in the past. Even if you're certain there's nothing inappropriate happening. That discomfort is real, and it has to be responded to.

Here's a principle I come back to often: no relationship benefits from one partner demanding that the other simply stop feeling a certain way. That demand always damages trust, regardless of what triggered it.

Glass uses a math metaphor I like: a negative times a positive is a negative. If your partner believes the friendship has gone too far (negative) and you don't (positive), the friendship has gone too far. There's no ground to stand on by insisting your partner is overreacting while continuing the friendship unchanged. Either the friendship has become something it shouldn't be, or you're continuing something that's genuinely hurting the person you promised to prioritize above everyone else.

Either way, the friendship is the problem.