I hate to point fingers at anyone as all scenarios are more complicated and nuanced than we can see from one side. But secrets almost always end up hurting someone, and if the daughter had to keep going back to ask because she could feel the explanation she was given wasn’t adequate, than to me the father was absolutely right to give her the answer she was seeking. My husband had an affair that ended our marriage. From the outset I told him I wouldn’t lie to the older kids who were teens at the time about the reason for our sudden rupture but that the 7yo was too young to understand. A few years later, I asked that she be told by him or by us together so that she would hear from the source and not have to find out from someone else. Children know so much more than they let on and as hurtful as it was to find out this truth, I also believe it gave her peace of mind to have all the dots connected. I think the father did the right thing here tho except that I wish he hadn’t made telling his son a secret after telling his daughter.