DP's son making me feel like I'm in a relationship with both of them

Do you have children of your own OP? I'm asking because you don't seem to understand how family dynamics work at all! You are living as a family unit now...and yet you're acting as if it's just the two of you (you and your DP) with the 12 year old having to fight desperately to feel seen or heard within this dynamic.

He shouldn't have to do this...if you're making tea and biscuits, you need to ask everyone, NOT exclude him and the tell him to get his own! This is not only rude, it's hurtful!

The same with breakfast...whoever is making breakfast should offer it for all the family...you are being very weird about this!

He's 12...he can (and should!) be included in conversations about mortgages and so on...how's he ever going to learn about these things if you shut him out??

I'm astonished that you don't see how bloody weird you are being here...and why his father isn't telling you how weird you are being!!

You moved in with them. You are the outsider. You upset their family dynamic. Try and behave as if you are a family - include everyone in conversations, meals and biscuits.

I totally agree with PP, he's trying to be included in what is his new family unit. Which would include being offered snacks and drinks etc. It's a little odd that you haven't considered this.

Assuming he's an only child, often only children are often more adult like. If he's living with his Mother when he's not with you and your dp- he will be the main person in his DMs life and vice versa so he will used to being involved in more adult conversations than many children and will probably mature quickly as a result.

All that aside not sure why you wouldn't offer him a biscuit with his tea.

This response is correct, in my opinion.

I cannot imagine making drinks and food for just one person who lives in the house - why wouldn't you offer/ask the child, OP?

As for him offering opinions when you discuss issues in front of him - is this the first 12 year old boy you've met?

Why would you be giving treats in front of him and not offering him one, or offering to make whatever his dad wants only? I can see why he feels indignant. Have you children of your own? It sounds like you haven't. This child doesn't want to be your partner. He's just a little human being feeling overlooked as well he might.

This. Neither of those show the DC in a bad light.

If there are two other people around then asking only one of them what they fancy for breakfast is really rude.

For nearly his whole life it has been just him and his dad. The conversations where he is chiming in, he was probably used to discussing all sorts with his father. You've moved into this young boys home, taken a lot of the downtime he would normally have with his dad and expect what? For him to quietly sit in the corner?

As for the other examples you've given, he is not looking to be treated like a partner. He is looking to be treated like part of the family. He lives there too.

Erm. Why isn’t he offered a biscuit or breakfast? It sounds like you just want it to be you and your DP?

would you not offer those things to a child of your own?

all 12yos are the same with conversations.

The examples you’ve given a pretty poor. As a mother I would ask everyone if they wanted a biscuit if I was getting one for me and my husband or if I was making breakfast. It’s pretty standard.

Could you describe what you think the dynamic should be like?

I can't imagine offering the adults in the house a drink, meal or snack and not offering the kids either. Of course he will feel left out if he isn't offered any breakfast.

And adult conversations should be had away from the kids.

Do you have children?
Sounds like a typical know it all , near teen haha

Give the kid a bloody biscuit! 🍪