We haven't had the level of misbehavior you've had unless you count the chronic thievery by SD63.  Of course, she's had the continual bad judgement with the debt, police incidents, family drama, emotional breakdowns, etc.

But every year, I see the crazy meter dial up around this time of year.  I know the holidays are tough on her with her kids all maintaining their boundaries, meaning few, if any, invitations for Thanksgiving and Christmas.  And, she wants to have gifts for her 3 kids and 4 gkids though she doesn't have enough to support herself and we subsidize her housing expense.

All this means we will soon be getting the crying phone calls to Daaad, both venting and angling for money.  She knows we give each of our kids Christmas $ and she typically gets hers early.

In the past, we have hosted a big Christmas for all our family, including hers, of course.  When she was still married, things weren't bad.  Since she and her exDH#2 split, it's been rough.  A few years, she was living here and it was just more of the same daily craziness.  Since then, I hosted an "UnChristmas" for her and her kids, meaning no gift exchange. That allowed her to see them.  The past couple years, she's hosted at her place but it's uncomfortable and the kids don't all show up.  Thankfully, last year she had to cancel due to illness and everyone seemed to breathe a sigh of relief.

If I sound heartless about a suffering person, maybe I am.  But I've been through such turmoil with her at holiday time that the season has been completely ruined for me and I often suffer depression in December.

I get being sad for DH.  We have never had this kind of thing to deal with regarding my SS-32.  Our version is my SIL. The  youngest of my bride's 3 younger sibs.  We took  guardianship of her when she turned 17 just after she graduated a year early from HS when my ILs signed their approval rather than requiring her to complete her last year of HS. If any kid needed that year to mature it is my SIL.  Their State lowered gradation requirements as a cost savings measure.  SIL had done a P2P summer in Europe after her Sophomore year of HS which gave her just enough credits to reach the decreased credit requirements so she could finish a year early with parental approval. My DW begged her parents not to sign. Sadly, their standard position has always been that they raise their kids to make their own decisions and to be adults.  Something that they failed catastrophically at with 3 of their 4 kids.  DW is their eldest and the only one who has had success in her adult life. #2 and #3 are hard working and at least not crooks like #4 is.

We brought SIL to live with us at the start of her first semester of University. The deal was we took guardianship, she would be a part of our family, we would pay for her University, we bought a car for her use, she would watch our kid after school (he was 12), did our lawn, and kept the house picked up.  That was a rough year. We did not tolerate her missing classes, we did not tolerate her doing crap academic work.  She did not like being held accountable for being a good steward of our money.  

After a year of school and turning 18, she ran home.  Since then, she has stolen $Tens of Thousands from family, borrowed over $100K in school loans for a degree she never finished, has been terminated from nearly every employer within  commute distance because she is smarter than everyone and cries that they terminate her for attendance but it isn't her fault because... you know... the kids, and is a toxic lying thief.  Her eternal mantra is "I'm spe,,,,,cial." in a whiny baby voice. I nearly blow chunks from the instant nausea when she goes into that crap.

It breaks my bride's heart that her baby sister is such a POS.  DW is thi executor for their Aunt's estate. SILs largest thievery victim  to the tune of the high multiple $5figures.  As executor DW will have to sue her sister to recover assets from her sister for the rest of the heirs.  To avoid that, DW worked with the Aunt to state that SIL gets nothing from the estate if her share is less than what she has stolen and that the estate will sue her to recover the stolen assets for the other heirs if what she has stolen is more than her share of the estate. 

This may prevent DW from having to sue her sister on behalf of the estate.

I feel for my wife in all of this. Though I am not sad about my SIL's crap other than that Karma has not come calling yet.

Drama is the effluent that ship people wallow in.  We can use that effluent and the drama to write them off, force their noses into the stench they stain their own life carpet with, and highlight how completely superior our life of quality is in comparison to their nasty existence.

By living well we set the example that they can model if they choose.  That choice is on them other than our choice to not tolerate their noxious crap if they choose to remain committed to it.

It is sad for our DH's, I think. I believe the situations overall are sad, or maybe a better word is pathetic. But nothing beats that feeling, like you say, of relief--and peace!  

Drama: "Look at me!" is a typical narcissist/borderline personality disorder move. The drama also serves as a form of purposeful punishment. In our case, it felt like, "You need to prove where your loyalties REALLY lie." Bad move on their part. 

I never would have tolerated the drama for years, and no one is a saint for tolerating all of that BS. Two years in, we separated, as DH was not handling the situation (granted, he didn't know what to do and was totally blindsided, but I had not signed up for any of what was going on). Marriage counseling and moving forward led to closing the door on BM, which led to (more) tantrums and fits from her, but we held steady. It was difficult. She tried to slither in a few times over the next few years but was not successful. We gave the skids more time and room because they were legally children and we knew they had been brainwashed. But five years into our marriage, when they were young adults, they were (mostly) out of our lives, too.

DH has seen the skids primarily outside of our home. . . about two visits a year for the past 15 or so years. SD visited us to "reconcile" but she really wanted money for her wedding. SS, who was much less drama-prone, has visited us sporadically--once every few years, I'd say. Then he, too, had the door shut on him, as his behavior oddly grew worse the older he got. I never attended a graduation (DH did). I did go to SD's wedding, and as I've said many times, we were treated like crap. 

Eventually, the wind seemed to have gone out of all of their sails because we stopped providing any sort of reaction. Things kind of blew up last year when DH had his health crisis (when I joined ST) . . . not so much drama but just exposure to them and their awful toxicity again. I don't mean to be melodramatic, but it was like having been a victim of a crime and then getting exposed to the perpetrators of the crime again. I guess through the years they have always hovered out there like some dark cloud, but we had found relief and peace--it had all been tamped down. Then the fire broke out again.

It's been a year of, honestly, recovering from that. . . DH recovering health-wise, and both of us recovering from what we were exposed to with regard to his kids. It was trauma with more trauma placed on it. It's hard to explain. It's like we've had to regroup and go from here. 

Those who put each other and their relationship above all else build lives of joy and adventure and a love for the ages together.  They do this for themselves, each other, and in spite of the enemies at the gate regardless of who those attacking barbarians may be.  They set the example of viable quality adulthood, strong partnership, and strong marriage for any minor and adult children of any flavor in their lives.

Unfortunately the kids are not bound to follow the example.  

Part of the success as a couple is not tolerating any crap from those who for whatever reason choose to violate standards of behavior towards the partners and their relationship.  Immediate confrontation of those disrespecting either  partner and their marriage regardless of who they are BKs/SKids, ILs, Xs, extended family, etc.... has to happen without delay and without question for why the enemies at the gate so what they do.

I do not care why they do what they do. I do not care about their fee fees. Only their chosen behaviors matter IMHO.

Congratulations to you both on your joy, dance parties, and life together.

Stomp on the roaches who swarm to detract from your joy.  They deserve and have earned nothing more than their final crunch when your shoe and your SO's shoe together ends them.  IMHO of course.  Hmmm. I wonder which dance step crunches the most swarming roaches?