I agree with those recommendations! I have a husband and a 9 year old and yes, the entire grad school experience was stressful. My biggest piece of advice is, if it is any way possible, finish your dissertation ahead of time! I am one of 6 interns at my site; 2 of us entered the year already defended. The other 4 are having a miserable time trying to balance work and dissertation and I dont see how I could have added family into that mix. Internship year is very difficult for many reasons that are hard to even put into words, but I think that it is very important to let your significant other know that you might have moments of extreme self-doubt and be over-emotional, but that this will pass and you will go back to being your balanced (maybe?!) self. Dedicating weekend time with my family was a must and I also try to not stay too late at work. I do get to work early, sometimes 6am, but that way I can get my work done and be home for dinner.
Last thing I can think of, especially given the fact that your child is so young, is to really work to mentally leave work at work. Whether you implement a mindfulness practice or use your drive home to transition from intern to mom, I think that it is so important to be 100% present for the sake of your child. If you have to spend less time with your family, you have to make sure it is quality!
Good luck!