In affair situation, neither of you can give the other any commitment for the future, even using the love word is tentative. Under this circumstance, the one puts out more, in terms of emotional involvement, gets hurt more. I think both of you have already proven that from your 12-year experience. Just reading from what you said, I would be a little hesitant pouring out my love if I were him(or you). If you want this affair to last, and not really working towards being together in RL, then you have to hold back and not pour all your emotions in, in case of what happened to you before happens again- abruptly end again, in order not to be crushed. You have to gadge how intense you want the emotion to be, engage you enough, but not hurt you. So I think he is still interested in you, but understandably not wanting to be hurt again.
You're welcome! I think all this pushing and pulling is to test where each of you stands this third time around, including what he said about his wife. Have you thought about what you will do or what will happen to you if your DH finds out? Maybe your AP is indirectly asking you that question. It is easier to invest more emotion if there is even a sliver of possibility that you two may end up together in RL. Otherwise, no matter how nice it feels now, it will end sometime, in some way, hopefully in a not too hurtful way. if he follows that trend of thoughts, especially after he could not even get you to promise a future meet-up, maybe he is intentionally pulling back a little. I agree, if he wants to, there is no way that he finds no time to write you a one-liner. It is a conscious decision. Maybe he is testing himself and proving to himself that he is not so attached to you.
In this situation, the one wants less, gets hurt less. If you truly want out, then end it with him. But if you are telling him you want to end just to draw out some affection from him, then I would advise you to just keep silent, like him. If he wants this to continue, he will contact you. Telling him you want out when you don't really want out will not improve the situation. Another way is when he contacts you, talk to him, heart to heart, and see if what you two want from this affair is the same. Communication is still important, even in an affair. :). It's hard enough for both of you. Why make it harder on each other?