AIBU to ask DH to stop doing this and is there a nice way to say it?!

He’s just trying to palm his DC off on you so he doesn’t have to deal with him. Tell him it would be a nice opportunity for him to spend some one on one time with his other DC when you take the 5 yo out. Watch him try to worm his way out of that! CF!

It's an absolute shame that all this is falling to the OP as the woman and mother when all she wants is her husband to stop assuming she's on call for a child he is also responsible for.

Oh and please don’t reply saying that he is not a bad man, he is the best husband in the world yada yada, these men are always “the best” whilst somehow simultaneously not.

Your DH has you well trained. You’re fretting about pointing out his unreasonable behaviour and looking for some magic, polite way to do it so that he doesn’t become defensive and turn it back around on you. In other words, he has taught you to keep your mouth shut to avoid his uncomfortable response.

In honour of International Women’s Day yesterday and all of the women who have come before you and have died for your right to be an independent woman, say it the way you said it here. If he kicks off, then fuck him. He is the one who will have two failed marriages under his belt and will potentially find himself having to look after two children alone on the regular.

Just tell him not to do it , can't see the problem. So what if he gets moody.

You absolutely nailed it. And in so few words! It really is simply, isn't it!

If he only sees his son at weekends he should be spending most of the time with him. If he’s really unable to for a few hours then it’s not unreasonable to take him out too most of the time to make sure he doesn’t feel unwanted.

Any chance he is getting someone into the house while you’re all out or is he just another sack of shit who don’t want to parent, just want to spread his genes? Either way….

Does DSS live with you? I get the impression he does and so it's not "palming him off during contact time" so much as "trying to make sure he doesn't feel left out" as OP seems to take DD out and leave DSS out of the plans a lot

A) I wouldnt be concerned with being polite.
B) how often does your husband take both children out on his own?

You need to integrate your blended family better than you are doing.

Going against the grain, SS is old enough that he doesn't need looking after. Maybe dh juat wants him to feel included in the family.

OP I find your post sad. What is wrong with asking your other child if he wants to go out as there is now something to do that doesn’t involve a screen? Why are you only planning activities for your five year old. The more the merrier in our house. I don’t exclude kids if they want to come and certainly wouldn’t be annoyed at them joining us.

“As much as I love DSS, please always ask me first before inviting him. Sometimes the activity may not be suitable or I may want to have a bonding day with DD. I’m sure DSS would like some alone time with his dad too.”

Agree
Dh does this regularly and she finds it annoying
Its sad and unacceptable that dh does this regularly it also means OP does this regularly which is also sad for SS and unacceptable

It works both ways but in the middle of this are two kids
One of them, the SS, doesn’t seem to have the right to either an invite or more importantly even the courtesy of a discussion about it. Whilst dd might also benefit from seeing her mum showing a bit of courtesy to SS by letting him know that they are off out.

Is it really so hard for a stepparent to talk to their stepchild

And No. that doesn’t let dh off the hook. But it could very well be that SS gets left out a lot, especially as OP says so.

You mean it's not a one off on her DHs part? And what do you mean she didn't want to speak to him...to who? Her DH chose to ask the kid instead of his wife, OP didn't ask the kid because SHE DIDN'T WANT TO!

And I think it’s really sad that you don’t prioritise one on one time with each of your kids. I can’t remember a single time as a child when I had a conversation or quality time with my mum just one on one as my sister (v close in age) was always there.

We were always the girls or the kids and I’m sad that we never got that time together.

As OP said in her original post ‘dh has an annoying habit’ of this behaviour.
So this isn’t a one off on OPs part.
This happens regularly

Its not, therefore, a case of she didn’t want to speak to him on this occasion alone. This isn’t a one off unusual occasion
My suggestion to OP is to talk to SS herself, she’s known him long enough.

Maybe next time DH isn’t working when DSS is there you should preempt his question, embrace what DH wants you to do, and arrange a day out with DSS. Leaving DH to spend quality 1-1 time with 5 YO DD. I suspect he might not want that either.

But she didn't want to this time! And there's absolutely nothing wrong with that

I didn’t say in my post that both kids always have to be included all the time.
Just that it wouldn’t kill OP to talk to her SS about them going out beforehand.

Not doing so just sounds like she doesn’t give a toss how he feels.

I really don’t understand why people think it’s OK for stepchildren to be so sidelined all the time…

Obviously he wants the house to himself or to not look after his own child. If he does it again just say no to the step son. Let your dick head husband deal with the fallout. Won't change otherwise. Unless he is actually a decent man and listens to his wife and hears what she's said.

If you haven't been able to talk to.him about this then that's the most concerning thing!

Agree.
They don’t all have to be glued together all the time but it is kind to talk to members of the family about what you’re up to. It’s kind to respect that at the very least

Or she could pre empt all that, act like they are a family unit, give SS a bit of respect and tell him herself.

Is it really so hard
Hi Jimmy, I’m taking Mary out for the day, you OK? What are you up to…..blah blah….friendly chat….Job done