Extended family helping with children has been the norm through much of history.

I can't imagine not ever getting away with my husband alone. We were married because we adore one another. And all moments on our own are treasured. My mom watches our kids a couple times a year. She does the same for my sister. My kids go to their cousins whenever they have the chance, and we all get some nice time with other people. I see their world expanded by the love others have for them. Cousin time is some of the best time of the year, whether here or there.
I can't imagine not allowing them that time, and thinking that we are the only people who adore them, love spending time with them, making more relationships. So, while you look down your nose on parents wanting time alone that might not be interrupted with crying or vomit, I'll gladly look at the people skills my kids have attained by the other people in their lives. And the fact that my husband and I love to be alone is just one of the fringe benefits.

As a matter of fact that was how we got one of them!