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Don't quit. I have played guitar for 45 years, for a living and with a day gig, with kids and without, and I've learned a couple of things that might help you.
First, the relationship between you and the guitar is sacred in its own way. It will keep you sane and give you delight when little else does. Second, getting good on guitar is the simplest of equations: time + concentration. If you pay attention when you play, and if you play often -- not fanatically, just often -- you get better. Third, if you're a parent working a day job, you have to find time between the cracks in your life. Fifteen minutes is better than nothing.
Fourth, use your drive time -- it's all you've got. Obviously you can't play guitar in the car, but you can listen to the music you love. Find some music that you can someday imagine playing, and absorb it. Just listen to it, even if you have no clue what they're doing. Someday it will come out in your fingers. And don't just listen to guitar music, listen to whatever music you love. Sing with it. Let it in, and let it out.
Fifth, be patient. Just keep doing it and don't compare yourself to anyone. Sixth, dabble in lessons. Find someone to teach you something, take a break, find someone else. Your job is not to be a slavish imitator, your job is to play. Seventh, laugh at yourself, but don't put yourself down. If you're still trying to learn "Stairway to Heaven" at 90, you'll be that 90 year-old-lady who plays the first four measures of "Stairway to Heaven." Is there someone better to be?