2nd miscarriage, heavy drinking
Miscarrying did not stop her and Olivier from trying to have a child, and one day she was pregnant again.
Unfortunately, in 1956 she again miscarried. As bad as her mental condition after the first miscarriage was, it was nowhere close to where she landed after failing to have a baby for the second time.
Vivien loved good wine and gin with tonic, and while she could get seriously drunk at a party, it had never been a problem. She had never got addicted, nor continued drinking for multiple days in a row. That changed when her mental illness started creeping in.
One of the signals that crisis is incoming was that she was starting to drink and smoke a lot, and then all the previous rules were being broken, and so were previous drinking and smoking records.
She was drinking too much and morning-to-late-night for many days. Doctors urged her to stop, or at least limit the amount she drank, because it made her symptoms worse, but she rarely listened.
The period after second miscarriage saw the worst of it. The actress lost a lot of weight and slept very little. She started looking like a ghost.
With time, she managed to pull herself out of it into the state of being moderately functional, but it would be a long stretch to say that she came back to her normal self.
After regaining some strength, Vivien took part in a European tour with Olivier and the Old Vic crew, but right from the start there were signs that it is too early to let her work again.
From the beginning, her state was poor and it only got worse as the tour continued. By the end of it, her bad form had a culmination in the train, where first she started attacking Olivier (and breaking a glass window in the process), and then screaming at other people she worked with.
One actress had to escape to a train toilet and close the door behind her, but that didn't stop Vivien from continuing to pound on the door and screaming obscenities at her.
At this stage, her illness was long past being just some mythical rumor. It was there for everyone for see.
The end of the Oliviers
After initial wonderful years between Olivier and Vivien, the physical passion between them burnt off. This didn't bother Vivien that much, but Olivier found himself increasingly estranged to her.
Sexual pleasure wasn't the only culprit here. Theatre was constantly on the actor's mind, always demanding more attention than he gives it, and Vivien's bipolar disorder took its toll too. She became huge responsibility, requiring constant care, thinking ahead and preparing for the worst.
During her attacks, he often served as a punching bag for her, with all kinds of insults going his way and objects as well. While his rational mind was explaining to itself these attacks as just episodes of mental illness, it's not always easy to maintain an emotional distance when being abused. This could contribute as well to Olivier growing increasingly cold towards Vivien with time.
Seeing the emotional distance growing between them was extremely painful for Vivien, for whom Olivier was the most important person in the world and, on top of that, a skilled actor she looked up to and whom she treated as a standard to try and reach.
As her mental problems grew, so did Olivier's unhappiness with their relationship. He began flirting and cheating on her. The more Vivien saw it all happening, the more her mental condition deteriorated. It was a vicious circle that just couldn't be stopped.
Jack Merivale to the rescue
When Olivier found himself a new object of worship and his marriage with Vivien was near its end, another man came to aid.
Leigh knew Merivale for quite some time and he had always been secretly in love with her, so when she became available, he took his chance and they begun dating.
Once the shackles were off, Vivien experienced a mini-revival. Being adored by Jack so much, she again felt like she's 20. The actress no longer felt capable of feeling mentally healthy and as happy as she was with Olivier, but this seemed like the next best thing. Her condition improved greatly.
Because her feeling for him was the schoolgirl kind of romantic, when that first rush of hormones said goodbye, she started feeling worse and her problems came back.
Fortunately for her, she stumbled into a true angel that without so much as a single word of a second thought took care of her until her last days. And with that support she felt stronger, which was probably the main reason why the worst that she has been under Jack Merivale was not as bad as what she was during Lawrence's term by her side.
That is not to say that Merivale was a carefree man - he saw plenty of that dark side of Vivien and his commitment was frequently being put to test.
Because Vivien Leigh died still relatively young (she was 53), it's hard to say if her condition would keep improving under Merivale, or if her illness would ultimately wear her down.
From what was gathered, it looked like it could go either way. Before the legendary actress left this world, she was somewhere in between - in a much better state than one would prognose 5, or 10 years earlier that she'd be, but still struggling pretty hard with it.
The actress' premature death caught everyone by surprise - she died at the age of 53.