Hmmm...never thought of it as something to plan for, but rather something you hope to happen. Then again, maybe my lack of planning is why I'm still single!
Do you have some job prospects where you can work less hours, doing something you love as much as medicine (or presumably will) and make as much money? If you do, you should do that, because those are rare opportunities. But nearly every job, especially professional careers, entails working more than 40 hours per week. So regardless of what you end up doing, unless you have some line on a 10 hr/week job which makes $75K/year, will "take up [your] time."
They have these things in medicine called "lifestyle specialties" - specialties in which you make a good living and have time to have a life.
There are even some non-lifestyle specialties like surgery in which you can work fewer hours per week (ie, working at a VA, doing a subspecialty).
At any rate, if your priority is your family, then spending as much time with them as possible will be a goal regardless of whether you go to medical school or travel around the world. Medicine can be inflexible at times (ie, during residency you have to show up, and can't necessarily take vacation when *you* want) but once you finish training, there is a lot more flexibility.
I might see what happens when you are ready to go to medical school and see if that wife has appeared, and what her thoughts are about it. She might have just as demanding a career and not be home when you get there.