The magazine deal follows a bidding war between rival publications and includes coverage of the ceremony, as well as Marsh's hen party.
> Kym Marsh 'signs three-year £500k Corrie deal'
The couple were rumoured to have put the wedding on hold following reports that Lomas had cheated.
However, they have now resolved their differences and will marry in August, The People reports.
Lomas allegedly begged Marsh, who plays Michelle Connor in Coronation Street, to let him prove his commitment and even offered to sign a pre-nuptial agreement to protect her cash.
"Kym trusts Jamie and says she does not need the pre-nup," a source said. "Summer weddings are booked up years in advance so Kym and Jamie may have to have the official ceremony in a register office before moving on to the reception.
"But the magazine obviously wants glitz and glamour so it's going to be an event to remember. The past few weeks have been make or break for Kym and Jamie. There was a lot of anguish and hurt but they are ready to walk down the aisle.
"This is the commitment they want to make to each other. But it's full steam ahead for Kym now and everyone's getting really excited about the big day."
The couple have a 14-month-old daughter named Polly together. Marsh also has David, 17, and Emily, 14, and Lomas has son Billy, 6, from previous relationships.
"Through all of this, Kym has realised how important her family are to her. She has got three kids and loves Jamie dearly. They have been through a lot together and are preparing for the biggest day of their lives," the source added.