Dave - sorry to hear things are so tough. Just keep working on detaching, letting your W be an adult and deal with things on her own.
One thing though - I really think you both need to tell your son what's going on. I know he's only 4 so you can keep it pretty basic, but I think not telling him is only making it harder on him. He's going to figure it out and right now I bet he just feels like you're abandoning him over and over, I bet. I know that's not your fault or choice, but I think if you tell him you'll ALL be better off.
Me 35, H 38; Together 13.5 yrs, M 7 Bomb 1 10/07/06 Sep'd 1/14/07 - 4/15 Piecing: 4/07 - 9/07 Bomb 3 10/11/07: Never loved you, let's separate 2/08 slowly improving 7/08 Piecing (7/25/08 rings back on!!) Current thread