Here is one way to do the Never Married event:http://ftmuser.blogspot.com/2010/05/how-to-enter-individual-...
Here is another:http://ftmuser.blogspot.com/2012/06/how-to-document-relation...
The only issue to consider here is "Are You Sure" that there was no children or that they never married. Is it possible that we just haven't found a record. (reasonable exhaustive search).
If a child died young, do you need to mark that person as "never married".
I am only suggesting that you think about the use of the two 'options' you asked for. The Blog only shows how you might do it, and I have. Young child, I don't need to mark it, but IF I find some indication, like a newspaper article, then I would use the options described.
I normally just "leave it open".
One users opinion.