Struggling with my child and my partner

[ParentG13]

I have two children aged 8 and I have been with my partner for 3 and a half years. We have hiccups now and again with my partner having two kids and with all 6 of us it can be abit of hard work but we work through it. But now and again my partner and my eldest 8 year old don't always get along with kills me. I sometimes feel like I'm torned between both. I love my partner very much and I obviously love my child. They don't always meet eye to eye due to my child's behaviour, they can be quiet rude, cocky and disrespectful towards me and my partner. My partner gets annoyed and then we end up arguing. I have struggled in the past with my child's behaviour and tried to get help from the doctors, school nurse, family support help etc but nothing. I am on my own with my children and struggle now and again but my child's behaviour has improved slightly as at one point I was in tears all the time because of their behaviour towards me and others. I just want my partner and my child to get along and I'm struggling as to what I can do. Has anybody else had this problem? Please help with some advise

So when your partner gets annoyed at your child for being "rude, cocky and disrespectful", you don't tell the child off but argue with your dp instead?

No course I tell my child off for the way they have been as that's not how I want to bring my children up. My child will apologise for what they have done but they won't mean it and continue to behave the way that I just shouted at them for. It's like we're going round and round in a circle

Have you tried talking to your child? My son can be similar but shouting and telling him off just riles him and makes it worse, sitting down calmly and talking about the action and its consequences is significantly more effective.

Do you feel you both have a united front when it comes to your DCs behaviour?

I've spoken to them loads of times and it goes in one ear and out the other. I've tried shouting, punishments, talking, charts etc but nothing works. My child sometimes thinks that they are the adult so maybe they feel threatened by my partner and try to take over?
What do you mean by united front?

I mean are you on the same page or does he play you both off each other?

No we are on the same page. Sometimes my partner will tell my child to stop doing something of they are in the wrong and I would with my partners children. If my child has done something naughty or cocky etc then my partner would tell me then I would speak to my child and try and sort it out.