I understand deeply. My parents delayed my driver's license until I was 17 because of financial tightness at the time, and that distanced me from some of my friends at the time. You know what I gained from that? I got to see who my real friends were, and even more importantly, I learned that not all friends are the same in a visceral way. I learned how to confront my parents in a way to communicate my viewpoint in a way they could understand. We learned together how to compromise and renegotiate our entire relationship, helping transition from child/parent to adult/parent.

You have two jobs as a parent: create a safe environment for your children and prepare them for the adult world that is wildly unsafe. Unfortunately, these two goals are both required and contradictory. A line must be walked. Too much deviation to one side or the other will cause severe problems.

That line cannot be prescribed. It's different for each child, but there's a big problem with how you put your point. You aren't trying to prepare the child for a dangerous and difficult world, you are trying to protect them in a different way, minimizing the other dangers. I completely understand. It hurts to see your child hurt. All you want to do is make the pain go away.

Instead of helping them avoid the pain of learning about relationships, you should guide them. Help them understand. They won't at first. Like a toddler throwing a tantrum that you won't let them stick objects in wall outlets, parents have to be the "bad guy" from time to time. Eventually, the toddler will grow up enough so that you can explain dangers to them and you won't have to do it for that thing anymore. The same applies here. They won't understand at first. Help them understand the dangers. When they do, you can teach them how to safely use the metaphorical wall outlet. Then you don't have to be the bad guy anymore.