Create a home gym if you're wealthy; buy a set of resistance bands (total cost: $30) and run if you're not (or just frugal and utilitarian). Wake up an hour or two earlier than when your kids do and do your cardio/lifting then.
It takes about two weeks to adjust to the decrease in sleep, but the well-being that exercise provides in my experience more than offsets it.
Right now at age 32, I haven't been able to go to gym consistently mainly because work takes so much out of my life/time.