I didn't ride when my kids (now 22 and 24) were young, but I did teach aerobics and live at the gym. I mostly did this at 5-6 AM and then went to work. My husband was always the morning person (when he was in town, since he traveled a lot) and when they were really little and he wasn't around, (under 5 and 7) I had a teenaged babysitter who would come to my house at 4:40 AM so I could go teach aerobics, come home and shower, and then wait for my nanny to come. They just knew that mom was at the gym... I would get up early on weekends and go at 8 AM, so it didn't interfere with any family plans.
My kids were very self sufficient and I never hesitated about leaving them to go ride when they were teenagers. By this time, my oldest was about to graduate HS and the younger one was already a ranked junior level racer. He was gone riding more than me! Of course, they never did anything to make me not trust them. I am a strong believer in not sacrificing your whole life for your kids. I've seen too many people who end up having no life and no relationship with their spouse when the kids leave, including all of my friends from AZ who are now divorced. Of course, we did a lot with them when they were growing up, but my husband and I went out just about every Saturday night alone, or with other couples when they were growing up. We still do now, but we also spend most of our time riding together. Some of our non-riding friends think it's "over the top," but while they are sitting there complaining about how overweight they are, I am out doing something active.
Sorry to digress!