No excuses though.....maybe our WAS need to change a little also.
Yes, they do. COG is saying that HE needed to change himself, NOT specifically so his W and he could be together but because COG needed to deal with his own demons.
Now, as a side effect his W found being with him more attractive than being without him. But if you follow his story it's clear that that was only the beginning for HER changes to her own life.
Without that step COG would have been the 'new improved' man trying to live with the same W that left him emotionally.
There is no guarantee that the WAS will deal with their own issues. None whatsoever. The only guarantee we can give out here is that when YOU deal with yours, your life will change. And when YOUR life changes those around you MUST change because they are no longer dealing with the same 'you' any longer.