What will you do if makita mo yung asawa ng isa sa mga kaibigan mo na may kaakbay/holding hands na ibang babae sa mall?

If I'm that close to my friend, I'll find a way to let her know about it as soon as possible. If not too close, I have to gauge how she would take my information. I don't want to do something that would invade someone's privacy, so I also have to be very cautious before I act.