Wayne Jeffs, aged 29, has not been seen since last Thursday evening.
His fiancee Carla Louise Holbrook, who is six and a half months pregnant, said his disappearance is totally out of character.
The couple had been planning to get married this Saturday, although they put the wedding on hold after finding out the baby - a boy - was on the way.
“He wouldn’t miss this baby for the world,” she said. “I just want him to come home.
Wayne, a plasterer, was known to have been on Eagle Farm Road in the town at 8.10pm on April 6 and then on London Road at 8.53pm. Since then there has been no signal from his mobile phone.
Carla reported him missing to police on Saturday and since then family and the community have been out searching.
“The community has been amazing,” said Carla. “I can’t believe the amount of messages flooding in and from complete strangers.
“I can’t believe how such a small town has come together.
“On Monday evening 40 people were out searching.
“It’s totally out of character for us to have no contact whatsoever.
Carla met Wayne six years ago and said the couple “just clicked”.
“We are best mates,” she said. “He’s very outgoing and funny. He wouldn’t miss this baby for the world, I just want him to come home.”
Police say they are becoming increasingly concerned for Wayne’s welfare.
Detective Sergeant Mark Stewart, investigating, said: “There has been no sighting of Wayne since he disappeared on Thursday and despite following a number of lines of enquiry, we have been unable to locate him.
“I’m appealing for anyone who may have seen him to get in touch with us, and I’d also urge Wayne himself to get in touch with us if he sees this, as his family are understandably very worried about him.”
Wayne is described as white, around 5’8”, slim, with brown hair. He was last seen wearing a blue top, blue work wear trousers, black trainers, and had a silver chain round his neck. He is also believe to have a blue hooded top with him.
Anyone with information on Wayne’s whereabouts is asked to contact police on 101 quoting the reference MPC/765/17.