If he thinks you need to talk about the relationship then what is the problem with that?
Next time he brings it up ask him what he wants to talk about...
Do you know that the most successful salemen are the ones who talk the least when speaking with a potential customer?
Think about that..
The key is that when he wants to talk about the relationship is to LET HIM TALK. Of course you need to be in the conversation, but again.... Say your pieces. short and sweet. Few words, but to the point. don't go on and on and on.. Let HIM go on and on and on. Be a listener.
Ask open ended questions...."What do you mean by that?"
Then let him go on and on and on about what he meant...
Then you say.. "oh, ok, that makes sense"
Pick your battles and when it comes to being a motor mouth. Most all of us have that problem of when to shut up.
I catch myself going on and on and on to my wife sometimes.. I then say to her..
"There I go again. Being a know it all"
She then says to me.. "Yes, but you are MY know it all"
See how that is done on both parts? HUMOR It works... Learn to be the one to say you are talking too much and learn how to answer the person that says they are talking too much...