My response a few yrs ago to you would be along the lines of, " What is he freakin' nuts? He wants to you move to Alaska and uproot the family, all to play out some he-man fantasy?" My mind would then jump to Monty Python's Lumberjack song ( a skit where these brawny lumberjacks end up singing about the joys of wearing women's panties, lol). And Alaska, well it's so darn cold, and it's isolated, and it's this n that, etc.etc.etc.
However, hanging out on the SSM board has given me a different perspective. There is ongoing discussion on what it takes to be a desirable man...in many situations the men have been supplicating to their wives' wishes, and are dismayed by the lack of vitality in their marriages, despite doing all the "right" things. There's stagnation and too much fear to stir things up.
Now your H has gone overboard in the other direction... he's pursuing his life's work, his passion,which can be seen as an attractive thing, yet it's marred by the lies and deceit you have mentioned. It's like Goldilocks...no one is finding the optimal amount of balance and movement; there's too little or too much going on here on the board! You are certainly justified in your fears and insecurities...but will you be missing an opportunity for growth in the marriage? Is there enough safety to take that chance? Is your H is in reality enough to understand some of your needs and those of your children?
One thing I would say at this point: do not consider going if you cannot tap into any excitement over the whole thing. It will be a failure. Your outlook is key.
You might want to post this thread on SSM; the guys there may have a better handle on what your H is going through and what it means for your marriage. I've just about had it trying to figure out men.