How on earth did you get this? I wrote, "If you really want to become a doctor, your wife should be willing to work with you. If she does not want to at all, it least you know your marriage will probably end up being a statistic." Please note the bolded words they are not absolutes, and carry a substantially different meaning than your interpretation. However, yes your interpretation is a selfish way to look at the world.
I did not say that she was a bad wife if she did not bend to his every whim. To clarify my statement, a partner whom is COMPLETLY unsupportive of a realistic yet difficult to attain dream; is selfish and probably not that committed to a marriage. You know they say for better or worse for a reason.
A good partner compromises and does not put their needs over the other individuals needs. If his dream is to go to med school, and he has a solid plan to make it work, understands the tolls it will take, weighed those out and decided that he needs this, a good partner would support him. According to him, he has already helped her get her dream. Now it is her turn to give for his, as he has dreamed of this for years. He implies that he is unhappy in his career; she should want to make him happy. They should work out a compromise to make each other as happy as possible.
Sorry for misunderstanding your intent. I largely agree with you, but I still think that medical school (and medicine) is a really big request to make of a significant other. Those of us who are already deep into the process know that it's a really long, hard road. Of course most of the work (and suffering) is on the person actually going through the process, but the significant other is along for the ride.
It's easy to say "if it makes your significant other happy, you should do it" but the reality is that the process of getting into medical school is nerve-wracking, and the stress doesn't end there. I can say for sure that my wife isn't smiling and laughing as much as she used to before medical school; I come from a "medical family" so I know how this goes and am confident that she'll be as happy as ever once she's nearing the end of her residency training, but that's quite a long time (seven years in her case, and I probably don't need to say it, but that could certainly be much longer).
Aside from the stress of having a crabbier significant other, there's the stress of potentially having to move (assuming a medical school acceptance comes from afar), of lifestyle change (returning to the student lifestyle - not very appealing), and as if these changes weren't bewildering enough on their own, you get much less time with your significant other. If you're not familiar with the process, I'd imagine that a person could be left wondering if their significant other is changing into a person that they don't really know or understand anymore. It's a frightening thought.
You make a commitment to someone in marriage. Ideally they would stand by you and support you through anything, but it goes both ways. When you choose this path, your significant other is going to be feeling it, too. Some partners are better about tolerating it than others; some people going through the process are better at buffering their partners than others. Nobody can say for certain what will happen, but I think it's perfectly understandable that someone would be apprehensive if their partner wanted to do this and it wasn't expected. It doesn't help that the internet is full of stories and sayings about how medical school ends nearly every relationship that enters, including marriages.
Saying all of that, stc55 should probably make sure that his wife is very much involved and informed with the process. Medical school is not a great relationship eater - it's a major, prolonged stress, but as long as a couple knows what they're up against, they can make it.
For what it's worth, the first two years of medical school seemed to be the hardest on my wife - she's now ending third year, and the stress levels have gone down massively. (I think the stereotype is that the first and third years are the most stressful, though.) We fully expect the first year or two of residency to be just as bad (if not worse), and we're wary of how I'll respond to the stresses of first year... but in general we're a low-stress, low-maintenance couple, and it helps that we both have the same end goal. As long as both people know what to expect and are in it together, they can make it.
True love conquers all, amirite?
Keep your relationship as a priority, make sure that you communicate and are open to be communicated with, and the relationship will be a source of positivity through your struggles. That's not limited to medical school, though - it's true for any challenge.