I was trying to avoid my ex husband at events. I say the bare minimum to him. I steer clear of him in general. When together we just make "niceties". Like hi, how about that weather. Well see you later. You don't have to engage with someone you are trying to go no contact with. You don't owe anything to them and certainly don't have to say anything to them. Disengage. Stay clear of them. 

Keep It Stupid Simple.  Unreasonable people cannot and should not be dealt with reasonably.

IMHO rather than ignoring the inappropriate behaviors, it is better to go scorched earth zero tolerance immediate ass baring destruction on these types when they pull their crap. Even when they are kids.  In an age appropriate manner of course.  Set and enforce the standards of behavior and standards of performance you demand from those in your life.  If they choose to violate those standards, it should be instant game on.  No cursing or yelling. Just directly calling them out on their crap and building an eternally escalating state of abject misery for them to experience based on their chosen behaviors. If they behavior reasonably, interface with them accordingly. If not...... it is game on.

Though for caring people this is difficult, you have to learn to interface with them as if you just do not care.

At family events. Be present.  Be radiant. You  and your SO be unassailably confident and demonstrably happy on each other's arm.  Whisper in each other's ear. Both to flirt, and to comment on the behaviors of the dirt-bags when they ply their crap. Laugh at each others inside jokes and comments. The narcs will lose their F'n minds over your radiant happiness with your SO and his happiness with you.  These are blended family Kidults. They matter no more than any other rude ill behaved adult should matter.  If they make the mistake of behaving inappropriately, being disrespectful, or being demonstrably rude to you or your mate, rip out their throats. Confidently, calmly, maturely, firmly, and immediately. Figuratively of course.

Full disclosure on my blended family/SParent journey.  My crucible to survive was my first blessedly child free first marriage.  I did not pollute my gene pool with my serially adulterous XW. She brought no toxic spawn to our marriage.  She did have one in the oven with her geriatric fortune 500 executive sugar/baby daddy when she moved out of our marital home and another in the oven at the final divorce hearing. She lost the first one tdue o miscarriage but wasted no time in reheating the oven with another.  She is on marriage #3, has 3 all out of wedlock progeny.  Her eldest and youngest conceived with someone other than her husband at the time. Grandpa sugar/baby daddy married her after their second was born and booted her ass out when she got knocked up while cheating on him.  Karma!!!!

I met my DW of 30yrs 3 years after my divorce when her son was 15mos old. We married the week before he turned 2yo. I am his dad. He asked me to adopt him when he was 22yo. We made that happen.  The SpermClan were toxic, PASing, nasty, shallow and polluted gene pool wastes of skin. Fortunately DW had left SpermLand to attend university and took my SS with her.  That is where we met and became a family.  We have never lived nearer than 2K miles from SpermLand.  We lived under a CO for 16+ years.  After SS-32 aged out from under the CO when he turned 18 a few months after graduating HS his SpermClan continued their manipulative crap so after a few years of adulthood he wrote them all off.  His mom and I are very proud of raising the man of character, honor, and standing in his life, profession, and community that our son is.

We tolerated no bullshit.  SS was raised with age appropriately enforced standards of behavior and standards of performance. When the SpermClan stepped out of line we ripped out their throats with every legal, social, and financial tool at our disposal.  DW made our marriage and each other the uncontested priority. SS was our top marital responsibility.  Priority and responsibility are two very different things.  We are fortunate DW, SS, and I have a very close adult family relationship.

So, make sure you and DH prioritize each other and your marriage and tolerate no crap from the ill behaved narc SKidults or their spawn. Or anyone else for that matter.

Focus on living your best lives together. Enjoying continuing your life of adventure and building your love for the ages together.  Living well is what we owe ourselves and our partners. Living well together. Living our best lives is also the best revenge against the enemies at the gates.  They choose to be the enemies. Let them live the instant escalating ass baring pain that earns them.  Make delivering that instant escalating ass baring pain your fondest hobby as a couple.

All IMHO and experience of course.

Take care of you.

I am no contact with my SO's brother and SIL. I ignore them or give a short polite "Merry Christmas." Usually, though, i do what they have done to me for years. Pretend they are invisible. SO's brother will try to bait me by giving me thinly veiled rude comments in front of SO's parents, when he knows i won't speak up (the coward...it's very much frowned upon by the parents to display rude behavior in public, and the parents are in their 80s and their English is bad so they don't catch the rudeness of his comments.) I just stare at him a few seconds then go about my business. TBH, i don't go to most things for this reason.  

Keep it brief- acknowledge "Why hello SKID and SKID-in-law. Happy holidays!" Then walk away. You were kind but you don't need to follow it up with anything more. They will find fault in ANYTHING you do and they will never recognize their own behavior as narcissists so be brief. And if neither of your paths cross at the gathering that's ok too- don't force an interaction. 

I am blantantly ignored by SKID and his bride - they won't even provide me eye contact. I pretty much do not say a word unless DH says somethign to me and then I have my go tos: interesting! wow ! or great! That's all i say and in the off chance they ask me a question to trap me I simply pass the question on to DH and say "DH, SKID has an excellent question- what are your thoughts on blah blah blah?" Then I tune everybody out. I have to see them once a year but that might change to no times a year...I am perfectly good with that!

Also- I really wouldn't ask them "how are you?" Don't open teh door for any dialogue. Just a hello and happy holidays! Hello and happy birthday!" Hello and happy summer soltice!" "Hello and insert-something-that-does-not-allow-a-dialogue."

only my OSS is the issue. The situation heightens around the holidays. It's difficult to be civil around anyone you've gone grey rock on. All you can do is be the polite person that you are.  You know, in advance, that whatever you do, whatever 'attitude' you bring to the time together with SD, is going to be misconstrued, dissected and talked about. Not comfortable but you know that going into it. My DH sees (and is disgustedby) his oldest son's (and daughter in law) behavior. It's a blessing to have a spouse that has their eyes open and aren't in denial. 

The only advice I can give you is be with them, set a time limit, enjoy the time as much as possible and then leave. You don't owe her/ them anything more than that. 

If it gets to the point where that isn't bearable, stay away from them. I've put the responsibilty to agree to and/ or plan get togethers with his OS on his shoulders and he doesn't want to make the effort because of how awkward the situation is. My DH and OSS are responsible for making things better. My DH has tried and there's nothing but 'crickets' from the OSS. 

I used to hate the term 'it is what it is' but the older I get, the more I understand and embrace it.

Good luck. You and your DH deserve better. 

Just ignore. My oldest sister, who was the mini-wife to our Dad and competed horribly with his girlfriend, especially when he was terminally ill, is a full-blown narcissist who attempted to turn every family member near and far against the rest of us siblings because she didn't get the money (read: more than everyone else) she expected from our father's estate. She went as far as to stop communicating with her oldest daughter, who refused to stop speaking to the rest of us as ordered. This is my niece who ended up in the hospital with COVID (with underlying health conditions) and who we thought was going to die, while her dear mother didn't even check in with her, send her a card, or say, "Adios!" 

Occasionally, there is an extended family gathering and the bitch shows up. We stay far from one another. I ignore her. Completely. I am totally comfortable with that. My husband is not. He is dreading a family wedding in 2025. I said, "Hey, bud, I suffered through SD's wedding; this is the least you can do for me." ha! 

Make the people who act like asses uncomfortable by . . . doing nothing.  

I have stages for people who have decided I'm the debbil, not my SS because we do just fine but others who are in my tiny world..

Stage one: friendly fun me.

Stage 2: reserved, still kind

Stage 3: polite stranger I've just met

Stage 4: person who has become so unimportant in my life that I give them a few words, very few and a blank stare, Not even polite stranger, stranger who just showed their ass in public and I can't avoid looking at. Same stare my dog gets when I step in his poop, we both know what I'm tihnking but I'm too good of a soul to say it. 

: 

When my SD35 was between the ages of 15 and 22 she completely shunned me while living with us full time. I didn't know what to do because DH was a yellow belly and the more SD shunned me the more DH fawned all over her. I didn't give a damn about SD but I was so afraid of her influence on DH that I was convinced that if I couldn't get her to love me, DH would divorce me. Oh, what a co-dependent fool I was! I tried everything. I came up with a plan to attempt contact three times a day and for over two years, it failed every time. DH did jack shit. In fact, he put it on me that I "kept wringing my hands over it." I realized I did not have a husband. I had a traitor and almost walked. 

I got a counsellor because I needed support on my way out the door. Counsellor had DH come in for a couple of sessions. Well, the first session that DH was at, counsellor told me right in front of DH that I'm to shun the bitch right back. Stop trying. No more of this three attempts a day nonsense because it just gives her the power to reject me three times a day and it reinforces her behaviour because she's getting off on the power to reject me especially since her father endorses it. DH sat up and looked stunned. Counsellor called him out for being yellow. Taught DH about silence being assent, so as long as he allows it, SD will continue.

When it came to handling SD, both the counsellor and my DH actually told me "if she gives you snot, give her snot right back." Well, that's what I did. I completely shunned the bitch right back. It didn't take long for her to notice. I also didn't give a damn that I shunned her right back at family gatherings. DH's family noticed too. I didn't care. It turned out that they started coming to me with their own stories about SD.

So, shun away! Match their energy. I had no shame at all in shunning SD while remaining totally engaged with SS33. He accpeted me and we had a good relationship, so I remained engaged with him. Therapist even said it would be good for SD to see that so that she can learn that there are consequences to how she treats people. 

She is not going to change. Now just disengage from her.  Invite her to your holidays. Say hello, happy holidays.  and jts become DH Job to do the entertaining of her.  Then say happy holidays and good night.  another year down 

...how so many of us are in the same boat. 

Steppy Monstery, I understand what you are describing all too well. I truly feel for the dilemma you are in! There are no easy answers. I have gone from saying "Hello", smiling (actually it was proably an involuntary grimace), and walking away to telling DH that I will not be saying anything. Period. I am warm, kind, and gracious...but I am not fake. I just can't do it.

I went so far as to work on Christmas Eve this year. (A benefit of my position is no holidays.) I did not want to deal with OSD. She can have her 'daddy' all to herself. However, not sure how that will go considering he has blocked her from all communication? Now I wish I could be a fly on the wall....