Being 10 years younger than you makes it just difficult to give you an advise. See, I would expect you to give me advise based on your rich experience.
All I can do is share with you some general thoughts that come across in my mind from time to time, being at work, whether spending time coding, or writing some documents, assisting the marketing and sales guys or dreaming about my $32 Million startup.
In my opinion, your loving wife and children are a startup. being happy with them and maintaining decent family and quality life is a great success these days.
I think, by now, understanding this point, you should get up from your chair and start dancing with joy and happiness for being such lucky bustard.
If I was finding myself in such frustrating position this is what I was might be doing, finding myself a long term contract (as self employed), securing my financial state and then, after a while in the freedom, not being abused by a stupid fat ass boos, the muse would probably be back. Ideas will pop up and the way to the startup is short.