Woah! Did you just copy/paste my mind or what? I am exactly in the same situation and feel exactly the same way as you! Every word and sentence you wrote describe me perfectly. I also sold a few startups, I'm both business and technical, can't get excited again, love Square, etc. We should hang out ;-)
I showed your post to my wife and she really thought I wrote it.
Please reach out to me and we'll talk. You can find my email on my about page. Cheers!