I don't think it's a good idea.

As a parent who is recently divorced there is no way I would have sex and when my daughter might overhear it. Sleeping kids wake up in the middle of the night sometimes. It's a bit different when you are married and the parents of a child, you should still take measures to be discrete but they aren't always perfect. If that isn't the case you need to just do it when the kids aren't home.