I don't put in a terrific amount of miles on my bike(s), but I cycle most days and love it. I only have spd's on my road bike, I can't get out fast enough on my mountain bike (the brakes are MUCH sharper), although that bike does have half toe clips on.
Anyhow, reading your post made me smile, with fond memories of my first road bike ride.
It near KILLED me!!
I live in a very hilly area, so I've had to get used to them, I'm not fast by any stretch of the imagination, I have to really concentrate on how my legs are moving, how my breathing is going - I find every hill a challenge, but I love it (sorta!)
On my mountain bike, I could get up many big hills with relative ease, I particularly found the very long hills almost theraputic! but the gearing is different on a mountain bike, they're made for hills.
Your husband sounds like a star - give him a hug from me All too often here, I see men who have flown up the hill, leaving their poor lady to either walk or slog without technique "why don't you help her instead of leaving her behind" is what's in my head. Try listening to him, don't just hear his words as you slog up that hill, feel them. It's only thanks to my husband that I've finally managed to get up some of the hills around here
Keep at it on the road bike, you'll be amazed at how fast you are when you do get back on your mountain bike, those hills will melt away.. but first you gotta do them on that shiny new road bike