Rachel Doran, 32, kissed and waved off Chris Mahone from the home they shared as he and 30 friends set out for Ibiza, Carlisle Crown Court heard.
-> More from the courts: Robbers threatened victim with knife after kicking down door to his homeBut when they left their local pub in Cleator Moor, Cumbria, and got to the airport they discovered there were no flights or hotel bookings and Doran, who had collected the money, had forged the Jet2.com booking confirmation form, stealing the £360 each paid by the groom and his friends for a three-day trip.
On Tuesday, Doran pleaded guilty to theft of the money and fraud by forging the flight details.
The trip, on September 6 2017, was 10 days before they were due to be married.
The court heard Doran suffered three miscarriages in the period leading up to the stag do, and this may have affected her mental health and behaviour.
She was given a 15-month jail sentence, suspended for two years.
Doran, who now has a new partner and works in a factory, was also sentenced to 240 hours unpaid community work and 20 rehabilitation activity days.
She must also pay £3,600 compensation to be shared between the stag party.
Passing sentence Judge Nicholas Barker told her: "On the face of it you have acted in a deceitful and callous way. You must have known the theft would be found out and the world would come falling down around you.
"You did all this at a time you were preparing for your marriage."
Earlier Gerard Rogerson, prosecuting, told the court Doran and Mr Mahone had known each other since school and began a relationship, and he proposed on September 13 2015.
The groom and his friends met at Cleator Moor Celtic FC clubhouse for drinks before the midnight transfer to Leeds Bradford Airport.
But at the airport at 5am they discovered the flights and hotel had not been booked.
Mr Rogerson said: "It was then it dawned on Mr Mahone what was going on and he realised no bookings were made.
"Paperwork was produced including a Jet2 confirmation form. When it was looked at it became clear it was a fake document."
Mr Mahone tried to ring Doran but she did not answer. She rang back later "wanting to talk" but was told to "leave him alone and he wanted nothing to do with her".
Mr Rogerson added: "He then received a text message stating, erroneously, she was pregnant."
In a victim impact statement Mr Mahone said: "The whole experience has left me embarrassed. I trusted her, I loved her at the time and put all of my trust in her. I've lost confidence, I find it difficult to talk to women because I'm scared of getting hurt.
"I feel sorry Rachel took others' hard-earned money too."
Police found Doran's internet searches included gambling sites, loan companies and a "fake ultrasound picture maker".
Kim Whittlestone, defending, said Doran suffered three miscarriages in 14 months.
"The impact on her mental health was significant," Ms Whittlestone said.
"It's clear they did have an impact on her state of mind. One can only assume as a result of these pressures she behaved in the way she did."
Doran did not set out to steal but began dipping into the stag do fund, the court heard, until she became desperate, when there were loan applications and bets placed to try to get the money back.
She said Doran has been "shamed" and targeted in her community, had left her home to live in a hostel, her family and friends had "washed their hands of her", and she had tried to take her own life.
Ms Whittlestone added: "This is a devastating case for all involved."