i've been pondering an angle on this topic for a while, i loathe the expression 'mother guilt' & i think it's a complete waste of time. You do what you do as it's best for your family, so why feel guilty about that. Who are you comparing yourself to & do you think they are judging you anyway?? No one knows your real, true, honest home life - if you're a working mother, or at home, or combination of both, whatever, it's each to their own.
Do your children suffer?? Just ask, they'll tell you & it might give you a chance to explain the situation so they understand better. If you work you might miss an open classroom/ concert, if you're at home you might not be able to afford piano/ karate lessons - i'm sure they'll still grow up to achieve great things in life, regardless of the damage you might feel you're doing in the moment.
*I say boy-friend, he's a lovely boy from her primary school who she has always hung out with as her number one choice of friend on weekends, it's in that a-friend-who-is-a-boy way, 'tis all.