"ghosting" just means ending all interaction without warning. not necessarily in the context of a relationship. one can ghost a job, a friend, or even someone selling things on craigslist.
For instance, you can ghost from a bar or party, which is essentially just disappearing without saying goodbye and trying to avoid anyone noticing you leaving. Also called an Irish Goodbye.
The phrase refers to when you are in the early stages of a relationship with someone you met online and stop sending any communication to them without notifying them beforehand.
"He ghosted me after finding out I have kids."