Just an observation and thought. But aren’t you precisely what we fear most in this, the judgmental public. What makes you think this lady and her husband would be embarrassed or ashamed of their activity? Maybe they are, maybe not. That, however, isn’t the question at hand. You’re skating on thin ice to even discuss sexual matters with a coworker. It’s even worse if you are in a supervisory position.
Don’t overthink this. In the OP, you said this couple merely glanced at your profile. You’re not interested in them, and they didn’t express any interest in you. This is a case of two ships passing in the night. She doesn’t know it was your profile, so you have nothing to explain.