There was something that he needed to do; he needed to try to recover his integrity in some way. But he did not know how.
The answer is obvious, let go his plan to push Elena into his role, step up himself and take responsibility.
I find it very disappointing how Donaldson kinda waves his hand to create a 'sense of mystery,' by way of a character's obtuseness.
As a reader, I just shake my head and wish for better, bur this is a pattern.
The narrative drives the characters every single time. Donaldson needs Covenant to be completely oblivious to the obvious at this moment, so therefore he is.