My Ex

I have been divorced from my ex for ten years but we have remained friendly and we still do things together with our daughter and her husband. My daughter is expecting her first child and is a high risk pregnancy so we do everything we can to keep her stress as low as possible. I have just discovered that my Ex may be addicted to pornography online. He doesn't know that i am aware of this and actually no one knows because I don't know what to do. My daughter is very strong and she Is an only child. She normally helps my Ex with things he needs help with in his life because he has severe Adhd. This is not something I can share with her especially since she's pregnant. I came on here because I really don't know what to do and I really don't have anybody to talk to about it. Porn addiction can really wreak havoc in someone's life and can seep over and impact loved ones. I know that I could probably talk to him about it and offer some resources to him. I don't feel like I can talk to one of his friends or his family. Do I just ignore it and allow it to impact his mental health and potentially impact my daughter and her new family? I'm angry because I think he's been doing this a long time and I didn't know about it. I do care about him and I don't want him to be hurt in any way. Neither of us have remarried or been in another relationship. Our little family is very close and I guess i don't feel like I can ignore it. I just would love to hear some sane thoughts about this. Thanks for listening.