I was setting up a new household for a townie sim that was living in the YA bachelorette apartment with a female sim from my main family and for the first time in my game play. She immediately dropped dead after woohoo with her new husband of hysterical death. He was able to get the grim reaper to revive her but she dropped dead again, so I exited to main menu without saving and upon reloading the game had her calm down in the mirror this time.
I then installed the no emotional death mod. I have had sims die in game unexpectedly by fire, and just went with it, but was not up for it this time.
I have MCC, so can kill sims anytime I want.