I can understand what you are going through. I used to love the Holidays, and now I fear them. My husband and I have distanced ourselves from his family in hopes of healing ourselves. We have heard the insults, judgements and the lies enough.
MIL and SIL have been the instigators, and now with their lies in order to cover up previous lies, they have FIL and BIL jumping right in the mess. We have heard the "excuses" that they think justify in some sick way their behaviors and words. Well, enough is enough. We have been threatened, lied to, talked about sworn at, insulted, and bullied more than we can handle. There is a line that they crossed. I could never believe the words that come from them. My husband must have been hard wired differently, b/c he is NOTHING like his family. It was impossible to have a conversation with them. You cannot have a conversation with an unreasonable person. I really don't think they know the difference from their lies, and what is the truth. They cannot even see that the words have consequences, or even CARE that what they have done has hurt people. It has really spiralled out of control once we stood up for ourselves, and said you cannot treat us this way. Perhaps you are lucky your inlaws didn't show. Hopefully that is a sign they at least have some amount of acknowledgement for what they have been up to.
I do know that I am lucky to have a husband like I do. When SIL said terrible things to him about me, he really knew we were doing the right thing. I guess that is their "las straw". The threats and Bible beatings didn't make him accept their behaviors, so they tried to show him what a terrible person I was. No son or brother would ever stand up for themselves, so I must be brainwashing him. I don't know what the aim of that was, but it really show my husband that distance IS a good thing. It all seems to be a cycle that they dont want anyone to break.
And some people will unfortunately WANT to see you FAIL, and as sick as that is, they deffinately DON'T want to see you HAPPY. I have seen a lot of that.
As often as this happens, there should be some type of national support group. We can share our experiances and help one another. I know it would be cheaper than our therapist! :-) I don know the books TOXIC INLAWS, and HOW TO HUG A PORCUPINE, THE DANCE OF ANGER and also EMOTIONAL BLACKMAIL have helped me. I know my family is NOTHING like this, and these books helped me to understand more about my in-laws.
Good luck to you!