Totally agree with all these points. Ever since my first daughter was born I made a similar decision but I still work less hours than you do. I end up working around 40 hours a week and have never felt compelled to work any more. I will work after the kids go to bed particularly when my wife goes to bed and I don't feel like reading for whatever reason.

My first obligation on this Earth is to my family and part of that means not being gone all the time at work. I do that for the kids but also for my wife. Raising kids is hard work and she needs my help particularly at the end of the day. This changes a little when the kids are older and are less physically demanding I guess but when you have small kids you really need to take your wife's feelings into account when deciding how much to work. She really needs to feel respected and honored in the decision and part of that comes from making sure she is in total agreement with the final decision.

Also if you're any good at programming companies are so desperate to hire you that they will accept pretty much whatever schedule within reason you want. You might not be the absolute favorite employee of management but if you're good people will respect you and your contribution.