Life on the road "Should I have told the truth or not?"

Today I was faced with the question of whether I should tell someone dear to me the truth about her other half. Well, I ended up telling her the truth about her boyfriend and father of her child cheating on her while he is away from home working with our crew. This just happens to be another crazy day in our " Life on the road". The past couple of days my friends boyfriend has been fooling around on her with a woman who works here at the hotel. My friend has been calling me because she was concerned about her boyfriend not answering the phone and/or calling her like he usually did. I told her boyfriend that it was getting very difficult for me to keep the truth from her about what's been going on and that if he didn't man up and give her the respect by telling her himself, I was going to end up telling her. Well today she called me and was very confused about what was going on with him and why he's been treating her so coldly. Just liked I promised, I told her the truth! Now she says that she wanted to know and she was glad that I told her. I want to know what other people think about this. Should I have told her or should I have kept out of it? What would you have wanted if you were in her shoes? Please give me some feedback and tell me what you think. I hope I did the right thing for my friend. If anyone has any tips that my help her in this time of need , please tell them! I will definitely pass it on to her.