With their first baby set to arrive later this summer via surrogate, Giuliana and Bill Rancic have started to prepare fast and furiously for their little one's due date.

Which, as the couple learn in this preview clip from Tuesday's episode of Giuliana & Bill, is easier said than done.

Both accustomed to a heavy travel schedule due to their work commitments (Giuliana pulls double duty on E! News and Fashion Police in L.A., while Bill travels the country for speaking engagements), the duo face the harsh reality that they'll have to cut out many of their cross-country trips when Baby Rancic arrives.

"We've got to start slowing this train down, because this child is going to be here before we know it and we cannot keep up this pace," Bill, 40, says.

Expecting their child via gestational surrogate, Giuliana, 37, admits that she isn't as on top of planning things as she would have been had she been pregnant herself.

"I think if we were the ones pregnant, it would be a little different because we'd know the delivery's imminent, but now it feels like it's sneaking up on us," she tells her husband of five years in the clip. "Before we know it, life's going to be really different."

Traveling to meet with their surrogate for doctor's appointments, the couple tell Us Weekly they can't wait to witness Baby Rancic's birth. "It will be the best moment of our lives," cancer survivor Giuliana enthuses. "This truly is a miracle baby."

Giuliana & Bill airs Tuesday at 8 p.m. (EST) on STYLE.