Partly why I say you need to not let him know your expecting his behavior is because it will be easier for him to continue this behavior if he knows you expect it.
I'm not a psychology major or anything by all means, but I do know that if you expect better from people, you will get "better", most of the time, and if you expect worse, then they will give you "worse". That is, if you give them actions or words that shows them your expecting these things from them.
Of course, your H is in another relm right now, so who knows what he will do, but still.
Maybe try to get some other male figures in your s4's life, because one, your son needs this anyways, and two, if your H knows he's spending more time with certain male relatives, or friends, maybe he will want to try to spend more time, or maybe he will realize he's "loosing" his son. Which in a way, he is.
Another thing that might be hurting you, is when you talk to your H about s4, are those mostly about how he acts out, or that he's a lot of work, and so on? I know that when you say these things you trying to get your H to see how much work you have to put into taking care of s4 and that your H isn't doing squat to help. However, this will also put a damper on how your H feels about s4 and if he's just hearing about the times he acts out, then it might make H feel more apprehensive about watching him, or make him feel like he's "babysitting" instead of being a father. I used to do this in the past, so I started trying not to talk about the bad stuff, and instead,I would talk about the good stuff that my H was missing out on.
What you really need to do right now is to try not to focus on all the times your H is going to "bail-out", but focus on your own R with your s4, and getting him involved with other respectable men, so that your s4 can see what a man should really be like. Cause right now, your H is NOT being a man. An whenever you talk to your husband about your s4 act excited about him and talk about all the things he's doing that H isn't getting to see. Make him sad that he isn't being a part of his sons life.
okay, gotta go again! good luck
Me 33 H 34 S9 S3 M 6 yrs (2gether 11 yrs) EA/PA 1/2006 DB 5/2006 H wants D 6/2006 H wants ME 8/2006 H "said" PA/EA over 8/2006 H erased OW off phone! 2/2007
"It is far better 2 choose humility & change oneself, than 2 wait in vain trying 2 chang someone else."