I agree--it depends on the school, to a certain extent.
My family life here at Arizona is fairly laid-back. Our class is close, and there's lots of support for my wife, my son, and my daughter (who is on her way in March).
Congrats. It's fairly laid-back here in terms of spouse involvement with the school. Meaning, if you wish, you are always welcome here at the school.
Typically my wife and son bring me lunch and we hang-out 4 out of the 5 days of the week. There's lots of grass around here, and several other students have their kids come during the lunch hour as well.
You can expect your wife to devote as little or as much time to her studies as she desires. Depending on her natural abilities, as well as her aspirations for post-graduate training, this may be one hour a day or 5-6 hours a day of studying--that much is left up to her (and you, of course).
We have socials at our dean's home about every other month, and you are always welcome to drop by our dean's homes and "hang-out" if you wish. To the extent that your spouse will have a relationship with the faculty, you may also have such a relationship.
PM me with any specific questions that you may have and I'll be happy to answer to the best of my knowledge.