There are so many reasons why this may be the case:
He doesn't want to stick the knife in Doesn't want to do the hard work Isn't yet getting pressure from the OW The reality of D might shatter his lovely fantasy world It doesn't make any difference to him - why bother He wants to force you to be the 'bad guy' so he can tell everyone that it was your idea He wants to see how things work out with OW before he gives you up totally - a firm plan B etc
The point is; we don't know and it is likely he doesn't know. Does it matter? No. Because what you do is not going to be dependent on what he is or isn't doing.
This is one of the main purposes of GAL. To make you see that you are strong enough to say 'I matter' I am not an accessory or a safe option to his narcissism.
Let's be really honest with ourselves. He thought so little of you and your M that he found his sexual gratification elsewhere. His personal pleasure was the only important thing. That's narcissism in my book. So, leave him to it.
We hear a lot here about not being able to control other people you can only control yourself etc. This is usually aimed at the LBS who wants to fix things and make them see the error of their ways. But don't forget that it applies to you as well; ie you are letting him control you. Is that what you want? Is that what you, or anybody, deserves?
You are fooling yourself if you believe this is about you. It is all about him. But only if you let it.
