Visiting wife's family 9 months after getting hitched. Was told "Oh, it's just a quiet get-together. No biggie!" and "You'll have the house to yourself and [brother in law], I [mum] will be staying at the boyfriend's place!"

Bearing in mind I'm British, intensely private and hate hate HATE noisy crowds and attention.

We did not have the place to ourselves, mom & bf slept in the room directly across from ours.
We were in their master bedroom. There was a drilldo in the closet.
They made a fuss when I set the aircon to 70F. I was melting.
They had a whole fucking party catered and planned for, without telling us, and near 30 of extended family & friends showed up. I knew none of these people. It was so hideously obsequious. To note: we had a friend home-bake the wedding cake. We told her mom. She bought us a really expensive and awful-tasting store one for our afterparty, nobody liked it. Here we are 9 months later being called out of the bedroom we were hiding in for a "surprise". Giant crowd of people and ANOTHER CAKE. "Oooh, cut the cake, cut the cake!" - "What, you mean like the last TWO FUCKIN' TIMES." We were that stunned some uncle of the missus' literally grabbed her hand and made her cut it, everyone was cheering like YAAAY MARRIIED!! and were both just... what the fuck is this nightmare.

Later some other uncle asked me if I was from "one o'dem socialist commie countries". I got up, turned, walked away downstairs and got stoned with the brother-in-law trying to numb it away with candyfloss-flavoured vodak and CoD on the xbox. Wife joined me about ten later.

So yeah no deaths or cheats but it was so hideously awkward and not one of the other dozy sods could see we were pretty revolted by the whole ordeal. Mostly I'm furious because we'd had our wedding & reception, and it was awesome, this was like a slap in the face as if ours wasn't good enough.