I don't have children, but when I do, I plan on following the bedtime schedule my parents set for my brother and I.
At seven, I was in bed at 7:30 on school nights, and I could read until 8:00, when it was lights off time.
On weekends, I was in bed at 8:00, and could read until 8:30, when it was lights out. From time to time I could sweet talk my Mom and Dad for a little extra reading time on weekends, but the in-bed time was firm.
There is very little seven year old appropriate TV on after 8:00 or so, and I think that was their reasoning.
Edit: No offense to your ex, but I think 10:00 for a seven year old is RIDICULOUS! During the week there are times that I go to bed at 10:00, and I can get by on about half as much sleep.
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