Also fortunately, we are both boring homebodys and she wouldnt really have a problem with me working on this every night.
But be constantly aware that your main "customer" in your life is your spouse, and then kids. People put up with a lot without making it clear, often.
Someone as an outside observer who can tell you that you're starting to screw things up and you will listen can be incredibly valuable, both for the startup and for the family.
I was thinking about what you are asking as well, but now I solved my problem other way - I employed myself in the company I identify with, I mean I believe in what they are doing and want them to succeed. This allowed me to get the feeling like I am part of the company; it's not exactly like "this is my startup", but similar. I already do not crave to create my own startup.