Watched during intimacy

My wife and I have only been watched having sex once. We were in a high-rise hotel shaped like an "L" and our room was near the bend. We had the curtains open that led to our balcony. After a few minutes of foreplay, she climbed on top and straddled me. Seconds later I saw a couple come out on their balcony just a few yards away. Within seconds the guy noticed us and pointed it out to the girl. I was so excited to be seen, but I didn't dare tell my wife as she is a prude when it comes to nudity. The excitement of being seen unexpectedly resulted in a memorable morning. To this day she is unaware that a pair of strangers watched us from just yards away.