I agree that it can be hard to distinguish reasonable sharing if as a Codie in recovery we are overcoming things like secret-keeping, the inability to lean on others, etc. Definitely all about finding the balance between the 2 points of over & under sharing.
One of the often overlooked root issues with oversharing can be that it's a seemingly counterintuitive way of decreasing vulnerability. Seems wrong, right? That by oversharing you would be INCREASING your vulnerability, right? Sometimes not. Sometimes that's a method of word-vomiting all over someone in a way that makes them keep their distance the same way they would if you had literally walked up to them & physically vomited all over them. By throwing out allll of your secrets & vulnerabilities you actually overwhelm others in a way that's subtly manipulative. Brene Brown calls it "floodlighting".