It's the age of presumptions. Connotations rule our linguistic proceedings and allow for us to easily categorize someone based solely on the weight a title carries. The word I am focusing on is "ex", as in a person you've dated or had a romantic encounter with that ultimately did not work out.
Some people cheat, lie, steal, and can be completely absorbed with themselves to the point of ignorant narcissism. Take care to acknowledge the first word of that sentence as it can provide a lot of information about the world.
I constantly sense a negative connotation associated with the word "ex", and for an understandable reason.
There are some exes (there it is again) who have cheated on their S.O. or have lied to their face. There are some exes who were more concerned about sex or themselves instead of building a healthy relationship.
After thinking about that truth, the next logical thought to come to my mind is some exes were honest, decent people who were in a relationship that didn't work out for different reasons. Picture this: a couple who are about to depart for different colleges in different areas in the country. Long-distance didn't work the first time because the emotional pain of being apart was too much, so they decide to end things. They've discussed the emotional pros and cons of each decision: stay together or break up. This instance I see only happening if the relationship has been an emotionally rewarding one, as an abusive relationship would certainly not have such an issue to discuss.
This is not an imagined scenario. I have gone through this, as tough as it was because it was the emotionally responsible thing for us to do. I can almost guarantee we are not the first nor only couple to have done this, which brings me around to my point: relationships can end for a variety of reasons, not all of them being because of abuse. You must decide for yourself the nature of the connection between you and your ex first before applying such a destructive label to their entire being.
Some people are half-decent and actually care about their S.O. Don't let such a stigma surround the word "ex" as it only leads to the notion that you cannot remain, friends, which is entirely untrue. You were the best of friends while dating, so why throw that away? Because you read some article that rejects answering a text from your ex (stigma applied)? Absolutely not. Trust only your judgment as to who your ex is, and don't let anyone throw all your past relationships through the "ex" wringer.