Surprise! (White) Michelle Williams is engaged. But in the post announcing her engagement and pregnancy with Fosse/Verdon director Thomas Kail a lot of people were surprised. Surprised and confused as a year and a half ago she was announcing her love for a completely different man, her new husband Phil Elverum. There were also people who never realized she was (and is?) married and others who didn't realize she had separated, especially as Williams is typically low key with her love life and doesn't do red carpets with her partners.
So using my my google-fu I reconstructed a timeline of the last two years of Michelle's love life and path to Thomas Kail which includes 3 engagements, 2 failed marriages, 1 pregnancy and 0 divorces (so far):
In early January 2018 Michelle Williams began wearing a large ring on her wedding finger prompting speculation that she was engaged... to businessman Andrew Youmans. She had first been seen kissing him in July of 2017 but when the engagement rumours started her team dropped a report that she had been dating him for "longer than anyone was aware of" possibly to make the engagement look less rushed (which now seems ironic). Though Williams never officially confirmed the engagement "multiple sources" did to US Weekly in late January. January is also the last time they are photographed together on vacation with her daughter Matilda.
In the September 2018 issue of Vanity Fair she revealed she had married in July... to singer Phil Elverum who uprooted his life and moved with his daughter to NYC after their quick marriage.
The interview took place in either late June or July of 2018 shortly before Williams eloped, but there is also some follow-up after her marriage where she talks about her new husband (I highly recommend re-reading the piece):
Obviously I’ve never once in my life talked about a relationship, but Phil isn’t anyone else. And that’s worth something. Ultimately the way he loves me is the way I want to live my life on the whole. I work to be free inside of the moment. I parent to let Matilda feel free to be herself, and I am finally loved by someone who makes me feel free.
Another fun tidbit in the Vanity Fair interview? She announces she just got offered the role of Gwen Verdon in Fosse/Verdon to be directed by Thomas Kail!
An interview with the L.A. Times mentions that Fosse/Verdon took 8 months to rehearse and shoot and wrapped in March of 2019 meaning Williams would have begun work on the show almost at the same time she married.
On December 2, 2018 Thomas Kail is honored at the Kennedy Centre and makes his last public appearance with his wife, actress Angela Christian.
In late April 2019 Williams reveals she has separated from her husband. People claims they have not been together since "early" 2019. An interview with Elverum in November of 2019 however suggests he lived in NYC for 9 months which would put the split around March of 2019.
Also in April Fosse/Verdon premieres. Angela Christian does not appear to attend the premiere.
In September Kail and Williams both attend the Emmys to support Fosse/Verdon (Williams wins but doesn't mention Kail by name, only issuing a general thank you to her bosses) Christian again doesn't attend.
December 2019 Williams and Kail reveal that they are engaged and expecting a child. It's unclear whether either have officially divorced their spouses. Congrats!
January 2018 - Williams dating (possibly engaged) to Andrew Yousman
July 2018 - Williams marries Phil Elverum, begins work on Fosse/Verdon
December 2, 2018 - Thomas Kail attends the Kennedy Centre Honors with wife Angela Christian
March 2019 Fosse/Verdon wraps
April 2019 - the Williams/Elverum seperation is made public, Kail attends the premiere of his show without his wife
December 2019 - Williams and Kail announce their engagement and pregnancy
Sources linked throughout the post + me and my sleuthing