The couple, whose divorce finalised last year, parted ways in 2011 after being married for six years amid rumours that Kutcher, 36, cheated on Moore, 51, reported E!Online.
"Demi is tapped into Ashton and Mila's wedding planning and she's telling friends that she's going to get out of town during the time frame of the wedding. She knows she'll have to endure hearing about the affair. But the wound is still fresh from their divorce," a source said.
"When she gets word about the exact date, she's booking a trip to the yogic spiritual center of India, Rishikesh, where she'll submerge herself in days of waking at 4 am, chanting, meditation, yoga by the Ganges River, light eating of only meagre portions of vegan foods and dressing in saffron coloured robes," the source added.
The 'Jobs' star is said to be expecting his first child with Kunis, 30.