This is one of the most relevant questions we've seen yet! This question can be seen near and far on the web as 13 Reasons Why just aired its second season and announced a 3rd shortly there after. While the show continues to receive mixed reviews, one thing stands clear. The show holds relatable to youth, because a lot of the topics are relatable. Parents are taken aback and continue to blame the shows graphic nature and reach on topics that may not be as bad for their children, but still get the same point across.
This questions is as old as time itself. Parents grow up and seasons change, topics change, but also, remain the same, but the disconnect between parent and child is still there. Somewhere along the line, we feel like were being to "clingy" or too "parental" and we nag, however, maybe that is the route to take after all. In retrospect, it may have been your opening right then and there to advise the kids, hey we can watch this, but if anything like this happens to you, please talk to me, we can help, we can fight it together.
Sure you might sound like a broken record. Maybe you think you say it too often, or that your kids are annoyed, but its almost your job to be annoying, and theirs to be annoyed. Its the circle of life! Don't stop talking to your kids, but also, don't apply their issues to your life. Try to remember, everyone learns differently and everyone responds and deals with things differently.
It sounds like you've started the conversation, so the only thing I have to say is keep doing what you are doing. Any chance you get to relate to your kids or let them know you can talk to your parents, it's not going to be weird, do it! Somethings they aren't going to come to you with, but you will know when something is wrong, just don't let other parts of life distract you from that. I feel like 13 Reasons is a great example of where the signs were there, but her parents, their parents really, were too caught up to realize that they were clear as day. Even the teachers were prone to brushing stuff off because they were often overwhelmed with too many students and mixed stories.
Hell some kids don't know what's going on in their own life! Their friends don't always know much better than you!
It does seem like you're doing all you can, and at the end of the day, that is all you can do. Make like 13 Reasons, and just start the conversation, and hey, next year, when they want to watch season 3, maybe it will give you more to talk about, and as each of them ages, you'll learn something new, right or wrong, that you can apply, or remove from the process, for the next!
No one is perfect, but it sounds like you are doing a great job already, so keep it up!