Do I have to be nice to DW's relative?

[DonaldTrumpIsABellend]

DW (I'm a woman too btw, to avoid confusion) has a relative who epitomises the phrase 'brass neck'. In the six years I've known them their behaviour towards DW, and other friends and family has had me like

For some reason, this person keeps getting a free pass for shitty behaviour. No one has ever pulled them up on it and so they carry on with impunity. Family ties and all that...

Anyway, I find this person abhorrent. There have been too many instances where I feel they've acted beyond the pale. And even if it hasn't directly affected me, it's affected people I care about. Or, it's diverted much-needed support away from me and towards them at critically stressful times.

Rather than have a big showdown or be actively rude, I've chosen to simply not engage with this person and remove myself from their sphere. Not hard as I don't see them often, DW mainly drops in to see them when I'm not around. I might have to be in the same room as them once or twice a year but am considering even ducking out of those occasions as well. I have absolutely no 'poker face' and I don't want to start a war.

This person came to our house today to pick something up from DW and I chose to remain out of sight instead of exchange false pleasantries on the doorstep.

DW thinks I was rude and should pretend to be friendly to 'keep the peace' and keep this person sweet.

I think I can do and say what I bloody well want, on a Saturday, in my own house and if I don't want to pretend to be nice to someone I don't like, I don't have to. AIBU?

(BTW it's not MIL. No MIL bashing here!)

Nope, you handled it perfectly. I have a friend DH despises. He thinks she's awful, she has no idea, he stays in his office if she's here with her (sometimes quite naughty) DCs. It's the only option which doesn't result in WW3 kicking off. YANBU at all. Life is far, far too short to be spent with folk you're not keen on.

This depends completely on how this person is related and how important this person is to your DW. If it a sibling that your DW is close to, you need to suck it up and play nice. Otherwise, it is no big deal if you were "just in the middle of something".

UANBU. In a previous thread someone quoted a writer who said something like 'if someone went around sticking pins into people would you say 'oh it's just their way?' Of course not'.

Emotional damage is more subtle than physical but is just as or more damaging. You don't want a pin stuck into you and won't be quiet if you see a pin being stuck into someone else. For whatever reasons of family etc some people have such nonexistent boundaries so as to allow a pin to be stuck into them. You don't have to be part of it.

Rosamund that is such a great analogy. I'm going to steal that one to try and make DW understand.