Hi Kevin!

As I can understand from your post you have changed in Permalink Settings the Custom Structure to “/blog/%postname%/” and all your links now have the “blog” in URL.

This has nothing to do with the theme and no matter what theme/plugin you are going to use the structure in the URLs is going to be the same because of that setting you made.

Because the logic to add the word “blog” to the general URL structure is wrong this is what I suggest you to do:
1) Remove “blog” from custom structure and leave only “/%postname%/”
2) Then create a category in your posts called “Blog” and assign the category to all of your posts and now only the posts will have the URL structure “/blog/post-name”