Awwww, sweetie. Stop for just a second before you move to Oslo, or Timbuctoo, or outer Mongolia! Because while a change of scene may be a great idea, it might also be the last thing you need right now... and to be honest, you're not in a fit state to think clearly about whether it is the right decision or not.
Firstly, let's deal with the self-loathing. I know that you are not old or boring. I can understand how you might feel that way, submerged as you are in the worries of a business, kids, and the daily routine, but you're NOT! The old 'you', who lived that bohemian life, isn't dead, she's just a starving and neglected part of you!!
Second, I understand you looking back on the past with fond regret - believe me, I know what that feels like! However, I think you probably made the decisions that you did (buying a house, having children) for a reason, and I am sure those things bring you some freedoms and joys as well as some burdens and responsibilities. I wonder if you are perhaps looking at your more traditional life through the imagined perspective of your friend, whom you think would be highly critical, and thus subjecting yourself to a tortuous barrage of imagined criticism, which probably doesn't reflect his real life perspective, but is a kind of vocalisation of your inner insecurities and dissatisfactions??
The key question is: what can you actually do? How can you regain some of that creativity and that spark, while in your current position? Before you move to Oslo, how about a poetry or art course once a week, or a sculpture workshop, or whatever you would just love to do given half a chance?
I know if may feel that life is supremely busy already - how are you to fit yet another thing in? how are you to afford it, temporally or financially? - but the question in my mind is: what happens if you don't? You're already struggling, and if you don't take time now, this may get worse and worse until you're unable to function.
While I am not in your shoes, there are similiarities between your situation and my own. One insight that I am trying to live by is this: we have one allotted span on this planet, and we need to use it wisely. There are ALWAYS ways out, there are ALWAYS things that you can cut back on or find ways around to doing the things that we really need to do. People - and I include myself in this - make out that all kinds of things that are completely arbitrary are fundamentally necessary (big cars, big houses, luxury holidays, dozens of lessons for children) and forget that time is really the most valuable commodity we have. Perhaps you can downsize in various ways to fund a bit of time off? Perhaps the private education isn't as necessary as you've thought? You are resilient and strong, so use those energies to find a way to breathe new life into that creative part of yourself that you've been neglecting. :)