My Host told me not to go somewhere.

She's had a fall out with that aunt and wanted you to side with her!

The "looks what you made me do" is classic domestic abuse.

I was going to say the same. “You made me do (bad thing) to you!” Very common part of abuse. I remember DDs awful ex pulling this on her.

Leave it be. Cut this family member loose if she doesn’t apologise. Her poor child.

I am concerned about her child because she's clearly unhinged / suffering from mental illness. Can you signal her behaviour to another relative close by who can check in on her?

The "looks what you made me do" is classic domestic abuse.

She's a lunatic.

I have an aunt that used to get jealous about me visiting other people when I stayed with her as a child.

I am sorry to derail slightly but I am shocked that you think that "you made me shout" is worse than locking someone in a building! Your mother was literally held captive, thats a "doing time" level of crime!

YANBU; this is outrageous of your cousin. The only explanation (not excuse) that I can think of is: Has your cousin possibly had a falling-out with your aunt? It slightly reminds me of my maternal grandmother who used to have serious quarrels with some of her relatives, and would then try to prevent my grandfather and mother from seeing them. My mother lived as an adult in a different country from her parents, and every time she visited, it would seem that her mother had made up with one relative but quarrelled with another. She once locked my mother in the house to prevent her from getting out to visit the relative who was currently out of favour! However, she never pulled this 'you made me shout!' type of stunt; that's really extreme.

If your cousin has not had a quarrel with your aunt, but is just ultra-offended at your seeing anyone but her, that is even more outrageous.

How old is her child? Are we talking about a new Mum here?

That's the worst I've ever seen her.

That suggests that you have seen her being OTT but not that bad in the past? Or that she has kicked off but not at you?

Something not right there.

The fact that she assumed that the whole weekend would be you spending it with her, the fact that when you "defied" her (her interpretation, not mine) she went off on one and then blamed you for "making" her shout at you in front of her child...... she has issues. She clearly thinks that if someone does something she doesnt like or want, she is entriely justified in shouting at them and that is far from normal. Yes it is exactly what abusers do.

Either there is a back story with the Aunt, she has serious MH issues or is an out and out narcissist abuser.

Have you contacted your aunt and told her what happened and asked her opinion? Given she is very close geographically, she may have more of an idea of what is going on there.

Is the aunt from the same side of the family? If so couldn't she have come to cousin's house to visit? Either way very weird from the cousin

Is there a backstory about problems between the aunty and the cousin? Have they fallen out, it’s the only rational reason why your cousin would behave in this very odd manner?

She said look at what you made me do. That's insane. The kindest way to characterise it is 'childish' but the truth is, this is what abusers say (and some of them believe). It's a good thing you're not hugely close with this cousin, OP, I'd give her the widest possible berth from here on.

Even if she comes back and gives you the apology you deserve, I'd say treat her with caution.

Or any indication she has BPD?

"You made me shout at you..."

Has there ever been any indication up to now that your cousin is a raging narcissist?

That's very bizarre most people would love a guest to have some alone time elsewhere as it's exhausting having guests ... is there a problem
Do you think in her life?

Do you worry about her mental health? As it doesn't sound a normal reaction. Unless for some reason she hates that aunt and she doesn't want to visit her.

Nobody “makes” anyone shout… they choose to do this. I suspect she is lonely and possibly finding motherhood difficult. Not your fault though.

@Mearabade you think what you think, she thinks what she thinks, you both think you are right.
(As I've said before on here.)
None of us know the full details so can't factually answer.

She asked you to come and stay… why? Is there a back story there?
Did she need you for some reason or expect/plan a wee weekend just the two of you?

The only reason I can even think why she’s react that way is if she invited you specially for a weekend just the two of you and she planned it accordingly for whatever reason, maybe she needed some support or something?

Did you tell her before you went that you planned to see your aunt? If I was staying with someone for the weekend, I’d let them know beforehand that I was going to have a coffee with my Aunt just so they’d know the plan. It’s only polite.

I’m not assuming you did anything wrong, it’s just such an odd reaction that I’m trying to figure out why.

It's hard to believe a cousin could act this way! Does she have previous for being mental?

You can't reason with that behaviour OP. Just extracate yourself and leave it for now.

It does sound very extreme - that she won’t forgive or forget. No one can MAKE someone shout at them. All you can really do is reach out and see if she will offer clarification or an apology

Reply “excuse me. You are an adult. I did not MAKE you do any such thing. You chose to become angry about a totally reasonable situation and you chose to yell. Don’t you dare put that on me. Maybe consider anger management therapy because you were out of control and it is more than a little concerning. Do not contact me again until you are ready to apologise for treating me so poorly”