I'm in a similar position to you, although I'm almost nine years down the line. I've spent most of my thirties raising a family and climbing the corporate tech ladder, doing jobs which didn't really interest me but paid reasonably well. I too have seen opportunities and ideas go to waste because I didn't think there was time to concentrate on them as well as home life etc. What didn't click was that I was spending so many hours at work that home life was suffering anyway. I'm now doing what I can on my own ventures and cutting back on extra obligations for my (full time) job. Previously I'd be the first guy to roll up my sleeves and pull a 24 hour session at work to fix an issue. Not now (although needs must on occasion).

Having an understanding partner can help. My wife is supportive of my efforts as we both realise that despite being financially comfortable at the moment, we will never be rich and I will never be completely satisfied carrying on in my current or similar roles. And who knows what will happen in the next 30 years? I may spend most of those out of work, unable to get a job due to my age. A fear of regretting never even having tried is a big motivator for me.

As others have said here, there is time to be found. Cut down on the TV. Don't work such long hours for other people. Get up an hour earlier than everyone else, especially at weekends. What I've found is that simply by doing 'stuff', I've become more efficient and more productive with the time I have. Ideas seem to be flowing more easily now as well. You can do it. Good luck.