Well, in my situation, when I was alone with SS (which wasn't often), he was under strict instructions from DH to listen to me and do whatever (chores, homework, etc) that DH asked him to do while he was gone.  DH gave the instructions on what needed to be done before he left.  If SS didn't listen, or didn't do as DH asked, he knew I would tell DH and there would be consequences when DH got home.  So, it was more like being a babysitter than being a parent.

And my DH would always believe me over him, and would definitely give him consequences, so it worked well.  

Disengaging for some is not easy but it's going to help your sanity and well-being so you will find a way to make it work for you.

I can feel the tension from my H because of it. It's like he thinks because I'm disengaging from his kids, that I'm also disengaging from him and it is just uncomfortable in our house lately.

You will feel tension and you will get resistance. You've been "engaging" these kids for so long that this change will cause everyone including your H to feel uncomfortable...but that's part of the process and once you remain consistent and get over that initial part, it will run a lot smoother. It will get worse before it gets better but you'll be glad you did. I don't know your details but think of it this way.....it's either you leave and never deal with these step kids again or you stay, disengage and work on staying a healthy mother and wife.

No guilt or regrets!  Your mental health and well being is priority.

If you get this figured out - Let me know.  I have a 27 and 29 year old SD's that really make things hard on our marriage.  They are not in the house everyday like your situation but they call and text DADDEEEE all the time.  Apparently, upon their own accord, they have made it known to me that they are only able to talk to their Dad during the day during the week( basically while I'm at work).  Don't know where this came from other than my husband doesn't like to talk and if he does he will answer the phone during the day because work is slow.  When I get home we do things.  I really need to learn how to disenage better!  The crap they come up with sometimes just sends me over the edge and I shouldn't let it.  

So, if you figure this out, let me know.  

I did disengagment light at first "go ask your father" and left punishments up to my DH. Unless she was doing something that was detrimental to me or my kids then I would intervene, but I went full disengagment once she bragged about lying to CPS so she could go back to living with meth mouth full time. After that she was a ghost in my home and I never spoke to her again.

As for DH the reason he feels you are disengaging from him is because now you are making him the "mean" parent, he has to be the bad cop and make the kids actually behave. My DH went through the same thing and I told him "DH it's not you, its your parenting. Welcome to being an actual parent, if you do it right, they aren't your friend they will resent you, they will get upset with you!"

I have done it where and when needed, so not all at once for everything. And not because I feared the backlash, but because I didn't think I needed to be completely disengaged.

For example, I do like to do laundry and I did everyones. But if I came to DH about issues with the laundry (nasty underwear) he just kept wanting me to handle it in different ways. When I realized he was just putting off dealing with it but telling me I wasn't doing it right, I quit. I only did my laundry and my DSs laundry (and eventually taught him to do all his own). DH didn't like it one bit. He spent a lot of time trying to guilt me into go back because he didn't want to do it and he didn't want to address the issue.

This year I trained myself to not say anything about the skids, maybe a slip up here or there, but overall nothing. It wasn't the skids, it was DH. Either he wouldn't address them being disrespectful (which they weren't much), or he got offended over the slightest question or comment (even as simple as being surprised they were going to BMs a day early when I had thought they were with us one more day, and not mean or happy or anything, just a comment).

However, I retained my stance when it was just me in the house that I was the authority. I look at it the same as if I had neighbor kids or nephews/nieces in the house. I would hold them to house rules so I hold the skids to house rules.

It's actually been really nice. I haven't asked at all about OSS. I'm curious why he's only been at the house four times in two months (and it looks like he won't be here much this month either before college starts). And I'm not gonna ask. My guess is DH is upset about it based on a different comment he made about YSS, and I'm not going to be the scapegoat for his bad emotions.

Advice.only is definitely right about DHs not wanting to be mean. My DH has said exactly that to me, that he doesn't want to be mean. I told him that if it bothers him so much to call it 'mean' he could call it 'parenting.'

When issues pop up that are unacceptable when hubby is at work and its out of control, my husband gets a message what issue is and to address it immediately.

often this is about ss cleaning up after himself because of mess and dangerous things he leaves around, ants coming to our kitchen because of ss mess. Or ss scaring my kids and laughing about it...

hubby knows there is no way i will allow my kids to pick up bad skids behaviour 

Send them to some type of camp. Sports camp, camp, camp. Anything to get them out of the home when DH is not home