As for acknowledging your responsibility in past mistakes in M. you will get an oppotinity i am sure. hopefully he will bring up the R and you just need to be prepared. Validate and accept responsibility. even if he starts blaming you for things that are not right, do not disagree. That will pass.
If you really need to get it out perhaps you could set up a situation where he is forced to bring up r or you quietly bring it up. I doubt if he will remeber who brought it up anyways especially if the talk is constructive.
