When I write posts I usually have to use non breaking space element in order to keep margins in between the sentences. In other words - the text looks good in my editor, it is with spaces, but when I save it and preview it - it is all together, without spaces. Why it is like this?
You should be able to add this to your theme's style.css and add margin beneath the paragraphs on the live site:
Hope that helps. Good luck!