How can I get toxic sister to leave me alone?

[Nomintrude]

Long story short, my sister is extremely jealous of me and fluctuates between occasionally being pleasant, and the rest of the time barely tolerating me. Whenever she's around (family occasions etc) it really gets me down because she just gives me the cold shoulder and sends out the vibe that she doesn't like me. This makes me feel ill at ease and like I can't relax and be myself because it will trigger her jealousy and resentment. She takes the slightest opportunity to go nuclear at me, always presenting herself as the victim, and sends texts make me feel like shit basically implying that I'm a terrible person. I spoke to her a bit impatiently at an event this weekend (which I shouldn't have done but it was definitely minor), and she sent me a text saying that I'd spoken to her with hatred, contempt and disgust. It was literally just me being momentarily grumpy.
Is there any way at all that I can put boundaries in place without causing more drama? She doesn't do the texting thing as much anymore because I walk on eggshells around her, but it's always there under the surface. On one previous occasion she threatened to use 'the fullest extent of the law and social services' to be able to see her nephew, my son, purely because she hadn't spoken to me for months and then out of the blue expected me to drop my son off at our parents' so she could see him, which I didn't do (nor did I say she couldn't see him in general however, and the thought hadn't actually crossed my mind.)

I'm actually wondering if sending a message saying that I will consider any further contact of this type as harrassment, because I don't want to deal with it anymore, it's so stressful and horrible getting messages like this and sends me into a spin emotionally. It's not nice feeling like no matter what I do my sister basically can't stand me, especially when she positions herself as the victim in such an extreme way that I start to question everything about myself.

Do you have to miss out on seeing your whole family? I just arrange visits so we don't overlap. Your mum and dad don't want a row do they? Tell them you understand that sis is going through a hard time and you don't want to add to that. Seeing as sis seems to find your mere presence antagonising then maybe you and parents should meet up separately, maybe on Boxing Day or something.

Ignore ignore ignore

If she speaks to you, at Xmas, just smile and nod. Do not engage.

Do not invite her to your wedding

Tell your parents and people who know you both that you I don't want to talk about her. If they try tell them again you don't want to know

Ignore the health messages, they are simply trying to suck you back in

She sounds like an attention seeking a narcissist who's been enabled all her life by your flying monkey parents.
Tell us - have they ever stood up for you in the face of her nastiness?
Have they ever pulled her up on her atrocious behavior?
No - they just keep making excuses for her and EXPECT you to keep being a doormat.....in fact they will emotionally blackmail you into toeing the party line.

You don't need to 'play nice' and be a doormat for the sake of family 'peace'.
There will never be peace unless you submit to being the scapegoat and dancing to their tune....and the only 'peace' will be the one they will be enjoying knowing that your narc of a sister is taking it out on you instead of turning her abusive behavior on them.

I have a member of the extended family who is like this, and just like in your case, the parents are enabling it.

As parents, their job is to gjuide their children, whatever their age, not to mindlessly peddle the 'support both equally' myth. If one of your children is being a prat, you tell them! Especially if it is affecting someone else in the family.

By supporting her, they are effectively abandoning you to her bad behaviour. This tells you stuff about them, and about why your sister gets away with this.

They don't deserve you at Christmas

OP they aren't supporting you both if they allow your sister to be abusive to you.

They aren't helping her as they are telling her it is acceptable to be abusive in close relationships.

They are definitely not helping you as they are telling you that you should accept abuse in close relationships.

In my large family there are siblings that don't get on and some of the relationships in the past have been abusive. Unless it is an extended family event we aren't never in the same room/plac. Then we politely stay away from each other and people have learnt to hold their tongues if they hadn't known to do so already.

I don't get on with one of my sisters. She actually made the mistake of criticizing my appearance in front of our eldest sister at one of these family gatherings. My eldest sister asked her loudly, so everyone could hear, to explain exactly what she meant.

In your case as your case as you have a partner and child you need to make your own arrangements for Christmas Day that don't include your parents and your sister. Just pop in to see your parents on Christmas Eve or in between Christmas and New Year, when you know your sister isn't around. If your parents ever trick you into coming over when your sister is there, make the visit extremely short using some emergency as a excuse to go home. Keep doing this until your parents get the message that you will be in the same room/place as your sister. If they question you ask them if your partner was abusing you would they be OK with it? If then explain to them that domestic abuse can happen between siblings, parents and children, and children and parents.

In regards to your wedding unfortunately you have to invite her. If she is stupid enough to accept then make sure you have a handful of friends - mixture of men and women - who know who she is and know to ensure she causes no trouble and stays away from you.

OP think carefully about your wedding. I did not invite one of my siblings and the relief was immense. I talked it through with my parents beforehand but not in a seeking permission way - in a "here is what's happening and why" way. It would be such a shame for your sister to spoil your day.