Divide segments

I sketched a closed geometry in Creo, like the skeleton of a part that will be extrude it in different proportions.

I did the Skeleton, it's important to me to keep this Skeleton, because I will use it as a part of a relation in later features.

The problem is, that I can't divide the skeleton (in that way I could work it in different ways). What happens is that Creo automatically close the section.

In the figures you can see an undesired parallelogram, I would like to divide this into 4 lines, just like the line in the middle of the parallelogram.

Note: I already tried the divided feature, and it didn't work.