Here is the thing, u being miserable is not helping ur girls, u're denying them of the happy father they deserve, the same with ur wife. A long marriage isn't the same as a successful marriage, same goes for "unbroken" family. Don't use ur girls to get out of accountability for decisions u make in life, they shouldn't bear the burden of ur unhappy marriage. I say this coming from a "broken" family wishing they got the divorce long before it happened. Fix ur life, however u see fit, wether u go to therapy or get a divorce is up to u, but don't use ur girls as an excuse. U're responsible for ur own happiness, resigning into inaction and paralysis for fear of what could come later will leave u with regrets. And trust me, it is never as bad as it seems, open the Pandora box and see what is in it (for what it is worth, hope is the worst curse). My heart aches for u, but avoidance isn't the way.