I find that it's hard to play anything but happy ever after with sims 4, because they literary suck at being miserable! Someone insults them, they respond with asking about their hobbies. A stranger breaks into their home to have a bath, well you have to greet them politely before you can throw them out. Even when someone is misbehaving your sim can't really get angry unless you stage it.
With that said, there have been instances when I've managed. In my one save, my sim fell in love and got pregnant, and then MCCC for some weird reason decided to give that sim a wife during the pregnancy. So here was my pregnant sim, in love, with a man who just married someone else! Well I decided to run with it and see what happens, and it was a roller-coaster. He got my sim pregnant with their second fairly soon after their first was born, while still being with his wife, then he got his wife pregnant with twins, then again with my sim... She finally asked him to leave his wife after the birth of their third child. He did, they were married, she took great care to include his twin daughters in their family, and then, after she had given him another two kids, he went and fell in love with a much younger co-worker. That's when she had enough, divorced him and kicked him out. I left him as an NPC after she kicked him out and he ended up having 11 children before he died (she married two more times to lovely men who just unfortunately died on her).
But my best tip for playing misery, is to give sims a few traits that does not match and then play them as the trait dictates rather than what the game does. So if a sim is a hot-headed perfectionist, they will yell and be angry because dinner burned, or because someone got a B on an exam. If you play a sim acting badly several times, I find they are more likely to do so on their own as well. Also the high-maintenace trait is perfect for un-happy sims, they are angry or uncomfortable all the time. Letting mood-deaths be on is also a way to create unhappy sims, since the person they love can die at any moment.