Yeah, I get that - I really do; but OP isn't the one signing the checks so he needs to shut it off at quitting time. Just because you have that millstone around your neck, doesn't mean he should, too. Whether a labor of love or desperation to thrive, that's a small business owner's cross to bear.Doesn’t work that way with a small business, as soon as you turn down work or can’t get it done it’s on to the next company and you will never get that business back from that person.
Also, being a SB owner is not an excuse to live for work and only for work. If a work-life balance isn't currently possible, consider figuring how to get 10% closer to it by (x_date).