Some people are natural "sharers". They have no qualms about giving the most intimate details of their lives, diseases, relationships, etc., to even casual acquaintances.
One example was a colleague who was telling rather graphic details of an argument she had had with her partner (who I have never met), and with the further complication that she implied repeatedly that I should take her side.
In a one-on-one conversation, how do you convey to them that this is more information or detail than you are comfortable with, without coming across as uninterested in them, or uncaring more generally?