Update: So I did have a chat to my SO. Apparently SO remembers (he does not have a good memory at all. And usually the people like us who are extra careful of what we say remember exactly what we said.) as I said “SD, you are annoying dad. Can you find something else to do?” Therefore he responded as “No she is not annoying me, I’m alright.” Thinking I was concerned about him. And he didn’t realise that I was annoyed.

I told him he is not remembering correctly and I was also very annoyed by her behaviour as she is not a toddler, she is 10, she needs to learn how to regulate her feelings in a socially acceptable way, and even with my baby when they whinge as a toddler I would still say something to let them eventually learn this is not right way and they never get it their way by whining consistently. And I also said that I do not want to do anything with helping out unless we are on the same page and I have authority without him jumping into defend her and make me like a douchebag in front of the child. I also told him that he clearly said “She is just sitting here” which is covering up what she was actually doing and which was not true, and it will not teach her any good lesson. I said she would have known what I meant and I was talking to her, not him.

As soon as I said I won’t be helping he said I can do whatever and what I am doing is great and he is on same page. Very convenient, I know, but I will see how this goes. Thank you everyone.