When leaving your children with other families, make sure that family has the same moral values as your family. If not your children will be exposed to things that will plant seeds of corruption in your children.
My husband and I rarely have an opportunity to leave our children with people we trust, so we wait for them to go to sleep for the night to have our quiet time together.
Yes our quiet time together is important, but our children's safety and purity are more important.
Children are not a burden, yes parenting can be stressful, they are a gift from God. We are responsible and accountable for their lives. What excuse will we have when we stand before God and He says, "Why did you leave your children with that family whose children exposed your children to pornography (whether hard or soft)?" or "Why did you leave your children with that family whose children disrespect their parents?" and so on?