I think I can provide a different point of view here. The kid's view.
I come from completely broken family. My parents divorced when I was ~20 after more or less 10 years of constant bickering, fighting, arguing and 'silent days' which were more like silent weeks/months. I am ~30 now, and while I more or less recovered from most of the damage and pushed my life forward, my sister is still on psychiatric drugs.
The thing is, this 10 lost years didn't come from nothing. Because economic situation in my home country was horrible in the late '80 and in the '90, salaries of my parents (they both worked for their entire adult life) would be enough to barely survive, but that's it. I mean paying for home, food, bills and very rarely some second-hand clothes would eat what they've earned completely. So, my father in addition to his normal job, took side jobs at renovating. So, when we were kids, he mostly worked or slept, nothing more.
And as much as I admire his stalwart and selfless sacrifice, the extent of this approach was a grave mistake for us all.
Frustration and fatigue are funny things. If You're strong willed, if You're dedicated, if You have a reason, You can take a lot of them. Really lot. Way more than You think You can. But You can never perfectly contain them, they are like helium in a balloon. They bend Your mind and Your personality in subtle ways, barely visible even for very good and very close observers. A little to harsh voice here, a not-so-good choice of words there. Over time, a person loaded with these frustration and fatigue starts damaging his/her relationships and unknowingly spreads those things to people around. They don't destroy the connection the way drugs or alcohol do. They poison them, and through them, the people around You. And then You're all tired of each other, scared that even a single word can ignite a bomb, and frustration and fatigue of constant clashes build up and the vicious cycle becomes nigh-unbreakable.
My father faced a nearly impossible situation and did the best He could, with best intentions. But the result is, me and my sister, we've didn't know our father as kids, because he either wasn't there OR WAS TOO TIRED TO INTERACT.
Your situation may not be as dramatic economically, but fatigue is fatigue and if You just take it over time for whatever reason, it WILL destroy You and people around You. The fact that most people need some private time, completely alone or at least focusing on things which regenerate them is that, A FACT. Use google scholar to find proper scientific publications to prove it to Your spouse if You have to, but find balance.
Cut Your private time a bit maybe, but make it good quality time and NEVER let it go completely. Set aside some time for kids, make this time regular, so that they KNOW it will happen again, that they can count on it like on sunrise. And this time too, make it quality time. Be fresh, be happy, be regenerated. They will profit from this thousand times more than from being forced to keep company to a person who is tired and doesn't really want be there - especially since kids are usually very good at seeing through the lies and facades of adults. Try to lure them into Your hobbies when they grow old enough (or maybe bit earlier), it's tricky but doable. My PhD advisor wrote his PhD with his daughter on lap - she was about 3 yo at the time and they both greatly enjoyed this. I got my fascination with science from my father - in one of extremely rare free moments he had, he showed me a block of very fun educational programs on TV when I was a kid. Optimize Your schedule and discipline to waste less time on stuff like shopping and cleaning so that You have more time for important things.
But never, NEVER EVER take the "act like an adult, suck it up" approach and firmly stop any people who try to push You into this, because it brings a disaster of such proportions that if You haven't seen it, You could never predict it.
And typical expectations of behaviour in modern western societies don't have much in common with reality and wisdom anyway, so following them is bad in itself.
To bring happiness to Your kids, You have to be happy Yourself.