Yes, and statistically, guys planning annihilation of their families/spouses never reveal the whole plan to APs. They may drop hints, such as, "I wish I were free and we could be together", but never do they reveal the whole plan.
I have already said it, and want to repeat. APs in these situations are at a risk, too. There is no such thing as "he killed this horrible woman to be with me". There is, however, "he killed her to be with me, he might as well kill me to be with someone else later".
His AP better cooperate, and all his previouis APs, flames, or whatever you call them, should step forward and talk to the prosecutors, too. Without knowing it, they might have been at risk as well.
CW is not the same as (obvously mentally ill) man in Australia who, having annihilated his whole family, spent several days with them, and finally, went to the police. CW might have own issues, but he was lying, he planned everyting meticulously, and he is not telling the truth even now. He planned, and accused his dead wife, and guess what, some view his version as the possibility. Logically, to me it makes no sense. I think we are obsessing over the same details because there is very little new information, so in a way, we have to wait till the trial to find out the details.