If your dilemma is whether or not to text your ex, our answer is no. Of course we cannot be categorical and 100% cut in the "no-no" you read because the situations are different. That said, there are times when satisfying your need to write to an ex can free you and help you move on. And in what cases can you write without fear of being hurt again?
One time you should write is when you owe the other person an apology. Think about how you broke up and your role in that breakup. If it was the result of a bad communication breakdown and you were at fault, or the relationship ended because you cheated, now is the time to apologize.
If after some time apart you reflected and understood better what they felt, it is not a wrong thought to want to express your forgiveness and the emotions you feel now. That's because now you can express yourself in a way you couldn't before.
Even if you don't feel like apologizing at all, a little time with yourself and your thoughts can help you figure out what ended the relationship. If you think there's a chance you can at least be friends, you can reconnect with him.
Having said that, it is also very important to consider whether this person will hear from you or not. If you feel that your relapse would do more harm than good, it is best to keep your thoughts and feelings to yourself.
Also, it's a good idea to only write to someone you've had a relationship with when you're very clear about what you're going to say and why you want them to listen. Moreover, when you are prepared to receive an answer you would not like to hear.
Source: Cosmopolitan