My 8 y/o son's behaviour around stepsiblings

[Oofy]

My boy is 8, he is an absolutely gorgeous, funny, sweet, caring, considerate little boy. He is doing well at school, he makes friends easy, and he always does what he his told at home.

Home is with me, a 'single' mum.

He sees his Dad regularly and has his family set up with him, his dad's partner and their little baby daughter.

Alternative weekends me and my son are at my partner's house with his 3 awesome kids. He loves being with us all.

All the kids get on so so well, they have the normal fallouts and fights but on the whole they all love each other and they're all similar ages, 8-12.

We, my partner and I, give them all lots of freedom but set boundaries and have rules. We encourage them to spend time outdoors and not just on Xbox, we play games together and go out on family days out.

My partner's 3 kids seem to just 'get it', they get the rules and they don't put up much of a fight when they're asked to do something (tidy up, take a shower, share the Xbox, go out for a bike ride).

But my boy, who is so so good and so obedient at home with me, puts up massive fight each and every time he is asked to do something so simple, straight forward and not even time consuming!

He will find a way of challenging us, backchatting us, being utterly stubborn and won't do as he is told.

I end up having to physically drag him from the sofa when we are all ready to go out for a family day out and he won't put shoes on, then ban him from electronics for the day, shouting and just pulling my hair out.

The other kids are just sick of his unwillingness and stubborn attitude, and it's putting all of us in a very tough position every time he resists.

I really really would like anyone who has experienced a stepfamily (we are two years in) or even if you've not experienced this, can you think of something I am missing here?

I don't have specific experience of a step family, but I think it is telling that he is only playing up when spending time with your DP and his kids.

Have you asked him how he feels about spending time with DP and his kids? In my experience good kids act out when they're unhappy, insecure, worried. I think you need to get to the bottom of what's bothering him to resolve the behaviour issues.

Are you sure that he's as happy as you think?

I think he sounds unhappy or desperate for your attention tbh. Attention (even negative) is more desirable to a child than none and I can see why he might feel more sibling rivalry jealousy as your partner's kids are a similar age and his dad's dd is a baby.

Are you as consistent and authoritative when your partner is around compared to when you're home alone with him? If your discipline is weaker (because you don't want your partner to see you angry) then many kids would take advantage of that.

I would personally cut his weekends down to every other weekend. You can see your partner when he's at his dad's.