I'm wondering, is anyone else married, young, and going into the MFA or already in it? I'm really interested in hearing about that experience.
As long as your significant other understands that you're going to be disappearing into the world of reading and writing a lot of the time there shouldn't be a problem. I'm currently in a low-residency MFA program and while I'm physically with my wife a lot more than I would be in a traditional MFA, I'm in a back room reading and/or writing a ton. I really believe that if you get into a program that demands a lot from you, your relationship will tighten or disappear. Sit down and talk to your husband/wife before getting into it and explain why you're doing it, where you're doing it, and make plans together so that your significant other is a part of the process. The more you value their opinion, the more they'll allow for your space.
Now, if you're looking for someone young, married, and in a traditional MFA program, good luck! :-)