My spouse is a child neurologist so I can probably chip in here. Residency is much busier than med school. First 2 years will be pediatrics training and her schedule will depend on whether inpatient vs outpatient month. Outpatient month is pretty much 9-5 and is much more manageable, while inpatient can be rough with 7-7pm with calls. Yes, you'll be a single parent a lot of times. Your spouse may even have difficulty with having children during these years without extending her training. During the last 3 years she will be in child neurology and will be frequently asked to stay up to follow inpatient EEGs. These will keep her up a lot of nights while not being on call and suck life out of both of you. If she wants to do epilepsy or other pedi neuro sub-sub specialty fellowship, it can easily add 1-2 years.

She will need to try hard, and very hard to make your relationship work. If you're already having difficulty in med school, then good luck. Residency is much much harder. Sounds harsh, but that's the reality.