Gary Winters, 45, posted a series of heartfelt messages on the social networking site urging people to rally round to find the 51-year-old who has now been missing for 10 days.
Mr Winters, who is understood to have split up with the NHS worker just days before she vanished, said he had conducted a comprehensive search of woodland walks and begged God for her safe return.
Heather McKay was last seen in Dechmont, Broxburn, with the disappearance of the “bubbly, sociable” mum described as “entirely out of character”.
On the day she went missing, Mr Winters wrote: “Please help to find Heather, missing all day, if you see her please get in touch.”
The next day he posted: “As you all know, Heather has gone missing.
“We are into our second day now, any help would be great. Please message me or Heather’s family or friends if you see or know anything please x.”
Last Saturday he updated: “Sorry I can’t repost, my laptop is in for repair. Please keep reposting, we need all the help.” He later added: “Heather McKay a full search done of the cottage and woodland walks done by myself and the police please help xxx”
Last Sunday he wrote: “Now day three, please help. Missing and missed, please help Heather McKay. Message all friends and family xxx.”
His poignant last message – posted on Monday – simply said: “All I ask is Heather McKay is returned safe today and well, please God please xxx.”
Ms McKay was on annual leave from her job at the NHS and was staying with a friend in Dechmont when she disappeared. She was last seen at 7.30am on Friday. When another friend called at the address an hour later Ms McKay was not there and had left her mobile phone behind.
In an emotional appeal on Friday, her children Andrea and Kevin Waddell pleaded with her to come home.
Andrea, 24, said her mother had been in a “short-term” relationship which had come to an end and had “perked up” after initially being “quite low”.
She added: “I don’t think [the break-up] is anything to do with what has happened. My dad passed away in 1999, so she just wouldn’t do this. She has been there for us ever since. She’d always talk to me. We’re more like sisters, best friends, than mum and daughter.”
Police have issued several appeals for information relating to the disappearance but say there is “no suggestion of criminality or foul play”.
Ms McKay is described as around 5ft 7in tall, medium build with hazel/green eyes and brown hair.
She speaks with a Scottish accent and has a small burn mark on her forearm and a small tattoo on her right shoulder.
She may be wearing a light blue Berghaus rain jacket, jeans and a pair of brown Hi-Tec walking boots.
Anybody with any information can contact Lothian and Borders Police on 0131 311 3131.
• TRIBUTES paid to a man who died after being hit by a bus at the weekend tell of how relatives are rallying round to support his “broken family”.
The 36-year-old victim, named locally as Ross Henderson, was killed walking along a rural road in Kirkliston on Saturday afternoon.
It has been claimed that he tripped and fell into the path of a bus on Path Brae at around 3pm.
Police are investigating the tragedy and have appealed for witnesses to come forward and shed light on events leading up to his death.
They are particularly eager to speak to passengers travelling on board the bus.
Mr Henderson died at Edinburgh Royal Infirmary. No one else was injured in the collision.
Floral tributes and messages of condolence have been left near at the scene of the accident.
One poignant memorial, thought to have been written by relatives, read: “Dear Ross, such a tragic loss. You will be sorely missed by us all. We promise to support the twins and your mum and dad and hopefully in time the new babies will help rebuild a broken family.
Sleep tight young man, Uncle Tosh, Auntie Doreen, Keiran, Gareth.”
A friend also left flowers baring the message: “Cannot believe I’ll never see that smile again, won’t hear that laugh again but I do have priceless memories of growing up with you that will stay with me forever. I will miss you mate.”
Several bouquets of flowers have been left beside the hand-written tributes as the village community tries to come to terms with the tragedy.
On the microblogging website Twitter, friends of Mr Henderson spoke of their devastation.
Keith Lesslie wrote: “Raising a glass to my mate Ross Henderson who tragically passed away earlier today. RIP big man!”
While Donna Dalgety said: “RIP Ross Henderson all in shock and disbelief. Thoughts and prayers to everyone who feels his loss today.”
Local councillor Lindsay Paterson said the death would come as a “huge shock” to Kirkliston and said there would be a “thorough investigation” into the circumstances of the accident.
“My thoughts are with his friends and family at the moment,” she said.
“In due course I’m sure there will be a thorough investigation to find out how this happened and to ensure that it does not happen again.
“It’s a terrible tragedy.”
Echoing these views, Cllr Alastair Shields said: “It’s very sad to hear of the tragedy that occurred in Kirkliston over the weekend. My thoughts are with the man’s family at this unimaginably painful time.”
• The Capital’s festival season drew to a close with the spectacular annual fireworks display lighting up Edinburgh Castle.
More than 100,000 fireworks were used during the 45-minute concert, accompanied by a performance from the Scottish Chamber Orchestra. Tens of thousands of spectators turned up at Princes Street Gardens and other vantage points throughout the city as the Virgin Money Fireworks Concert provided the festival finale. The Edinburgh International Festival took £2.83 million at the box office, an increase of nine per cent in sales income, making it a record year.
Jonathan Mills, director of the EIF, said: “We have had a fantastic month. All of the festivals together have made a great contribution yet again to the reputation of Edinburgh, the enjoyment that Edinburgh citizens have and the welcoming of many people from all over the world.”
It takes a team of 15 pyrotechnicians seven days to lay out the fireworks on 17 different levels of the castle, from the ramparts to the top of the Castle Rock. Highlights included an opening volley, three 200ft-high rippling red comet stars rolling across the sky, and a “waterfall” feature which consists of 70 firing units laid out for 118ft across the castle. Lasting one minute, the display descends 131ft down the Castle Rock.
Councillor Steve Cardownie said: “The traditional firework display, along with superb musical performances, is a fantastic way to close yet another successful Festival.”