You dont have to be super affectionate to be the better alternative. In fact, if the attention isnt wanted, he will find it repulsive... which will make you feel awful. You shouldnt be mean to him, you should always be decent and respectful and kind, but you want to be aloof, why will he want it? Because men want what they cant have, and you need to act like you are moving on and just fine without him. Im not saying that you should date.
He has betrayed your trust in a pretty major way, he needs to earn it back. Why does he deserve for you to serve him dinner after you have spent the entire day taking care of 3 kids and a home, while he is flirting with someone on the other side of the country? The dinner is there, and he knows how to spoon himself some spaghetti. Its not mean, mean would be serving yourselves and putting it away before he gets any. Its about not treating someone who is being disrespectful of you, your marriage, and your family, like a good husband.
When you do talk to him, I think that it sounds like your doing pretty well. Keep it upbeat, if you have been critical in the past, compliment him when it is warranted. And you be the one to end the convo. It sounds like the convo went well, and those things can be really good for your positive mental attitude.
As far as fixing when you have been so critical in the past, I think that you should start asking for help again. And if he doesnt do it in just the "right" way, let it go. If you fix it while hes not looking he will notice, and he might be paying attention when you first start making these changes.
Im sorry if it sounds like some of this will not make sense, but when there is an active A going on, most of this is about making YOU ok.
I guess I gave the wrong finger to the wrong man...