Where are my line breaks?

I just searched my site for an old post and realize that it, and several of my old posts have line breaks that were originally there removed. I can only guess this happened during an “update”. Here’s an example:
http://kymberleedellaluce.com/letters-voice

Also, new posts won’t put in line breaks unless I force them with an html line break which is ponderous.

Is there a fix or plugin I’m missing?

Thanks so much for your help!