It all depends on your goals.
If you want to spend more time with your spouse/kids/family, then you need to put that first. I hope you're aware that the time spent with babies is unlike when they're older/bigger and therefore less dependent, so it's worth treasuring. Once they go to nursery/daycare/school, you have a lot less influence and quality time.
If you've got a great idea for an iOS app that could potentially earn enough to make a difference to your life, that sounds like a candidate for vacation time off work to get it done and perhaps several evenings a week where you negotiate with your spouse that you're left alone to have interrupted project time.
Finding a balance between these is hard, but it can be done. For example, after dropping the kids off and then going to work, do a full day with a short lunch, you could then come back to do evening routine with them. After they're in bed, you could have some time to be able to crack on with various programming projects. Obviously, your wife won't get a whole lot of your attention with this arrangement, so weekends should be reserved for quality family time, and a decent proportion of any money you make on the projects should be spent treating the family.
Whatever you do though, I'd advise against giving up the day job unless your iOS app has paid off the mortgage already and you have a year's worth of savings, as the market is a rapid-moving target.