Shakandbake
Hey Bangarang,
I think you already know what you want to do, so that is a good start. I, however, am still struggling with my decision. PLEASE keep me posted as to how you phrase your rationale, as I can definitely learn from it.
I was told by a highly reliable source that schools speak with each other constantly in formal and informal settings as the admissions circle is very small (think 100 people or so at top 15 schools). I was also told that it would be unlikely (but not improbable) for an ED school to let your other school know that you have reneged on an ED offer. The word of caution was given to me that I do not really have a very valid reason for not withdrawing application from other schools which is part of any ED application. I believe this to be true for you as well.
Honestly speaking, in my opinion and take this with a grain of salt, 2 years is a long time to be unhappy and short amount of time to be happy. Your full scholarship affords you the flexibility to do whatever you chose to do after graduation w/o pondering upon how you will pay the dreaded loan. Go with you gut. If you decide to call school A, please be careful as to why you decided not to withdraw your application.
I am rooting for you to end up where you will be truly happy. Please post on this forum once you have taken any action to mitigate your situation, I am very curious and interested

Shakandbake,
I have a wife as well so I've been empathizing with your situation, and I thought I might be able to provide an alternative perspective.
If you and your partner both apply as a pair, the school should know that despite applying ED, not admitting one of you is basically like not admitting your 'team' so rejecting any part of the team is rejecting the whole team.
The whole reason there is a space in the application to indicate whether you're applying with a partner tells me they understand that you are applying as a pair, and in talking with the admissions folks I would stress that you don't want to be away from your wife (which you would have to if she goes to school somewhere else).
At that point the dilemma is not that you would prefer a different school but that you're not in a position to choose any school over your wife. I probably wouldn't tell them outright where else I applied since that's not really the issue at hand, but just let them know that you applied ED in good faith and without your wife you'll be unable to attend.
In my mind, that's a reasonable decision that any person can understand, and if it were to come up at any point in the future I would feel totally comfortable illustrating the dilemma and why I made that decision. Also, if they come back and tell you they would rather you leave your wife for two years they were probably going to steal your soul at some point so it's better to get out now
Hopefully that helps, and good luck! I know it's a tough place to be.