I'd strongly disagree- this relationship may or may not work out, but that MD is forever. If you aren't married, I will always say to go for med school, as you'll hate yourself forever if the relationship doesn't work out and you passed on your only chance at becoming a doctor. Given that the vast majority of relationships in people's early 20s do not work out, those are odds I'd say are worth skipping on and just going to med school.
I'm mostly with you here Mad Jack, but if they're married than THAT is supposed to be forever, or at least vows were taken to attempt to treat it as such, and so then one must decide what they will or will not do or need to do to keep it together. Or they are taking your approach and career or bust come what may to what may be a first marriage in their 20s (I didn't catch if that were the case)
The MD is forever but it's usefulness might not be.
You could lose your marriage over this, find yourself too disabled to work or some other **** out of luck with that MD and have nothing.
Or, you forgo the MD to keep the marriage together only for the "in sickness and in health" bit of the vow not upheld by your spouse, in which case you still have nothing.
It's a classic dilemma, the "security" of family vs "security" of career.
Either one can let you down or die leaving you alone and miserable.
There was a married person who worked at the school who was in a car accident with family in the car, woke in hospital from coma to find their spouse and two kids dead, just like that.
You can't always have it all, and it's up to this person to decide what to pursue, what they might lose either way, how OK they are with any bad case scenario that might arise.
I know someone who gave up a very pretigious professorship because after 6 mo long distance and a lot of long pauses on the phone that long distance med school would spell the end of the marriage ultimately (they were on different coasts). It came down to career or marriage, and the career was compromised.
You guys really need to have a heart to heart with yourselves, be realistic how good you are at connecting via phone/skype/texting/email/holidays/where to spend holidays/vacations long drives/ finances with long flights and determine what expectations each of you would have re: long distance, how far the distance is you can tolerate, your respective sex drives, history of cheating or how well you can each rely on other expressions of sexuality (sex talk/ skype to each other, porn, reading erotica, masturbation), how frequent and what modality to use to communicate, and how that plays in, what if anything you would do if a rough patch was hit (counseling might not be feasible, would one of you quit to keep the marriage together?), and definitely what plans if you can't match together (would one of you pursue something besides residency with the MD?)
Without a lot of self awareness, maybe trial long distance, or knowing how far the distance will be, and knowing that this means 4 yrs at least and easily up to 7 years, this can easily go south.
The only way to prevent disaster here is a fair amount of introspection, honesty, and communication.
I highly advise trying to get into the same school, or one within driving distance, figuring out if you can afford short flights often, attendance policies and vacation schedules of schools (once you hit the last two years this will be impossible for visits together, you'll mostly be cutting down to weekends and have 60-80 hr work weeks even if you can do away rotations at one another's schools) and think about ultimate residency/career goals.
What if birth control fails? What chances of an unplanned pregnancy and what will be done to accommodate that?
If you don't do all of the above introspection and just start a school a plane flight away, and don't have a firm plan to either couple match together or not at all, or know that not couple matching that way means another 3 years long distance, and that without considering the above advice the chances of a relationship surviving 4 years long distance, and maybe another 3 bringing you to 7 years, without someone quitting, can be the end of the marriage, and without thoughtful consideration it will be, if you just dive in I would say the chances of destruction are high.
It's not impossible but without enough foresight you may as well go camping in the arctic without more than a ski jacket and a tent.