Wow, your post is so spot-on for me as well. I'm a very antsy person. The job thing (I have a career I love, and did complete grad school for it, but purposely chose a career where I could move literally ANYWHERE in the world and do my job.) Kind of self fulfilling prophecy there.
I'm constantly in search of a better option. Just recently I decided I hate our place and want to move. Before, we up and moved to Alaska. DH was not happy but now he's more into it than me... I'm ready to move to a new state (/country), he says we are just getting started here.
I also have moments where I picture what it would be like to start over. And like you, I would never do it and am completely committed to my marriage and family... but still... I picture it sometimes. (PS I think this is normal, and I don't sweat it.)
For me, I have struggled with anxiety disorder (panic attacks) that manifest themselves in the form of obsessive thoughts and behaviors. In college I was a compulsive door-checker. The neighbors would ask me if I was okay... I would get to the end of the walk, turn around and check the door, then walk to the street, turn around, get to the bus stop, turn around. I actually had to plan in more time for getting ready because I knew my compulsive checking would make me late. Also the stove/oven. Compulsively checked that while at home.
I was prescribed as-needed xanex, which helped me get over a real hurdle with this. I still get panic attacks, but work through them. Maybe once or twice a year are they so bad that I take half a xanex (my script is the lowest dose available, btw). I think becoming a parent helped me put my life experience into perspective too... don't panic with a child, just take care of business, or they feed off of your negativity. You know the drill.
Anyway, long story short, DH and I just had the worst fight of our lives. PS we've been fighting a lot lately (don't worry, this is going somewhere good, promise!). Okay, so I'm such a planner, I want to talk about plans and then go do them. Moving, new job, new state, new this, new that. Onwards and upwards! Drives DH nuts. The talking forever, the unrealistic plans (some of my plans could legitimately be categorized as "crazy schemes" for a lot of mainstream America). We also have struggled with his drive and ambition (he has none, or rather, very little) and I have WAY to much. Out of balance, we are, to say the least.
Okay, so this worked so great. We sat down, and we discussed our long and short term goals. It was a date, we made plans, no kids, etc. Just us, hashing it out. This was SO GOOD. Quite of few of my goals were bumped to the long-term category (+5 years, which is really where they belong, and I needed a reality check on them) and then we narrowed and re-fitted some of our short-term goals, which gives me something to work on and fantasize about.
That's really it - fantasizing. I need something to imagine and envision when doing the day to day slog. If I have too many fantasies (or none at all), I pick fights, get really crabby and am generally unsettled. This goal-setting meeting really filled that need for me. And now I can be agitating for goals of DH's too, which is helpful, not annoying (I hope). Also there are multiple goals for one time period, so that helps too.
So, minor success story for you. Sorry about posting a short novel, but hey, I was on a roll!