Getting a PhD is hard. Any job that requires time will take it away from something else you could be doing. So your spouse is likely to be taking over tasks you used to do. Some spouses will resent that.
In addition, because you are tired and under stress and lots of pressure from your department, most people react to that stress by becoming a less nice person. The spouse and the kids get the brunt of that.
Some people make it easier on themselves by taking ten years to finish instead of four or five—whatever the standard time is in your discipline. Others find ways to be very disciplined and organized so they can do what they need to do and get it all done.
It really helps to be well organized and disciplined. You can be as efficient as possible and you can make sure you work instead of doing other things. Your highest priority has to be the degree and you have to live that, not just give it mouth service.
Most of the people I know who make it through the programs where I work in the minimum time have fellowships and don’t have to work. Those who work take an average of an extra year or two for every year they have to work. Then there are unknown variables like data gathering. If you want to go through fast, do secondary data analysis. Be a statistician. That’s how you get through a PhD fastest.
Qualitative research almost always takes longer. It is also almost always compensated at a lower level when you get a job.
Anyway, these are the kinds of things to work through and some of the issues to think about when juggling a PhD with family and work. It is a lot, but it is also doable.