Cantstandit, I soiled when I was a child and grew into a teenager who didn't bathe/wash her hair, etc. I didn't soil as late as your stepson but maybe I can help a little.

When my mother was sick and in the hospital for many months when I was a toddler, I became untoilet-trained :-) and my father and I had a "battle" about it (says my aunt) where he'd use laxatives but I'd outlast him and when I was finally in clean underpants, would go then (nothing like a passive-aggressive toddler in training :-) Anyway, that all got resolved, my mother died and my father remarried when I was 5. When I was 7, he was in the Navy and went to sea for 8 months! I started soiling and boy was it embarrassing, being at school (had a teacher have to sniff me out one day)! We even had our own bathrooms in our classrooms so it wasn't like I had to go down the hall or anything. But I'd never raise my hand.

The big thing is that I didn't know why I was doing it, it wasn't "intentional" and I felt powerless to stop. My stepmother abused me horribly over it (have you ever had to take a bath in a bathtub with only a couple inches of water and several shovelfuls of garden dirt in it, complete with bugs and sticks, stones, etc.?) and was on my case constantly. When my father came back, it straightened out. But, when I became about your stepson's age, my stepmother and I started battling about bathing. I would work very hard a "pretending" to bathe without doing it.

I think your stepson is in a will struggle with you over his mother. I don't know what to suggest but I'm pretty sure your stepson is unhappy/miserable and has no clue why he's doing/not doing what he is and wishes there were some way out.

Were I you, I would cease avoiding him, cease commenting on the problem and go to therapy myself to see how to "help" by my interactions with him to shift your stepson's behavior if I could. I don't know what happened when he was 6 and started this but I'd look at everything then and see what "similar" thing is being perpetuated now. Back in the early 1950s when I had my problems there wasn't any chance of therapy or "understanding" what was going on and my stepmother just thought I was being difficult like you feel about your stepson. I was protesting my father going away in the only way I knew only there was no one to make any connections and either reassure me or "help" me in any other sort of way.

I suspect something happened with his real father when he was six and your wife's/his mother's pretending that nothing is/has been happening isn't helping, as you're very aware. But it may be that you can help the most but I'd go to a therapist and see how you can change your behavior with your stepson so it is most beneficial to both of you (and maybe get some insight into what, if anything, you can do to get your wife interested; maybe some joint therapy or something).

It might get very ugly as I don't know how you can convince your wife to get her head out of the sand and "help" other than to threaten to leave which will ultimately threaten her son. Could be he feels somewhere responsible for his father leaving, etc. but being a child there are no words for that, only "action." If you can get yourself secure so you can reassure everyone else honestly, that's what I'd aim for. At this late date, I don't think words alone will do it though.

Are you familiar with Parent Effectiveness Training (PET)? That might help you, don't know http://www.enotalone.com/article/4535.html