SheFly, I am new to cycling and ride with a great group for beginners. A few weeks ago I hit the wall because of dehydration. I was so thankful to have experienced leaders with me to A) tell me to get off the bike, I wasn't going any further, B) Get me rehydrated and back to the shop safely in a car, and C) to encourage me to get back on that bike the next week!
If I hadn't found this type of leadership, I probably wouldn't be riding, because I would be too nervous to go out on my own. It sounds like you are offering that same type of support to your team. Ultimately, you have to feel comfortable with the responsibility that comes from coaching them, but I bet they are very thankful to have someone like you and your hubby leading them. Any sport or activity carries some risk and parents should be aware of this. Hopefully these parents appreciate your efforts!