You can view the entire route on Google Earth. You should probably zoom in to a "Street View" for a few places like the Eisenhower Tunnel, Vail Pass, Glenwood Canyon (just east of the town of Glenwood Springs), and Debeque Canyon (just east of Grand Junction). Then your husband can see exactly what I-70 looks like and you can see the scenery you will be missing if you use I-40 or I-10 to avoid Colorado.
I drove 2-lane US Highway 6 from Moab to Denver in the 1960's while they were building the Interstate. It took 10 hours to cover that distance; Grand Junction is now about 4 hours from Denver. And we had to go over nearly 12,000' Loveland Pass (now that's a road with steep cliffs and hairpins), even in winter, until the Eisenhower Tunnel opened in 1973. So, it's hard for me to imagine anyone not wanting to drive I-70 now!