How do you tell the difference though? My WS seems to be doing both. He brought up legitimate concerns in our relationship (some things I really am working on changing within myself), but is also doing a lot of the wayward things (I never loved you, I never wanted this life, there is OW who makes him *so* happy who he is living with, not sure if I'm happy with her because I was so unhappy with you etc.).
I guess at the end of the day, my response is kind of the same. Let him do what he needs to do and focus on myself and fixing the things I think I need to fix (learn to try and control things less, listen more, appreciate, get treatment for my depression etc) but some of these I can only really work on if he comes out of his fog and agrees to try and work on the relationship.
Sparks I have struggled with the same question. And then I realized that we ALL have legitimate issues in our marriage. But we either suck it up, talk to our spouse about it, or get counseling. Those are the healthy responses to dealing with legitimate issues. That is what you do. If you go wayward, then you use those legitimate issues as an excuse to justify your own behavior. Doesn't mean the issues aren't real, just means that you are using issues - that everyone in every marriage has- to justify being a cheater. If you talk to your friends with "healthy" marriages you will find that everyone has issues. Everyone. Not everyone cheats, not everyone spews, not everyone uses those issues to justify bad behavior.
Go ahead and address your issues because it is the right thing to do. But do not accept the blame for your partner's behavior.