If this ex used to be your best friend, there were qualities about them that really appealed to you as a person.
The fact that they hurt you badly doesn’t erase your history with them as your best friend.
When you are trying to assess whether you should stay friends with this ex, it is best to look at your relationship with this ex as a whole.
Think back to how your relationship was when this ex was just your best friend and not your partner.
How was that relationship?
Was it fulfilling to you?
Did you trust them?
Did you enjoy most of the times that you shared?
Did you feel that you could confide in this best friend with just about anything?
If your answer is in the affirmative, try to sit with that for a moment.
Now, think about how the both of you got into a romantic relationship in the first place.
Was this something mutual?
In other words, did the both of you really want to get into a romantic relationship?
Was there someone who was pushing for a romantic relationship more than the other?
If you think back to this as objectively as you can, it is possible that you may discover that perhaps you were the one who was more excited about getting into a romantic relationship with your ex.
If this is the case, your ex may have never really wanted to transition the relationship from that of being best friends to that of being partners.
They may have been truly reluctant to do this.
Hence, it was only a matter of time before they would hurt you.
This doesn’t mean that they began the romantic relationship with the intent of hurting you.
However, in time, they may have become resentful enough of the relationship that they ultimately acted in a way that led to you being hurt.
This is often what happens when two best friends get into a romantic relationship and one of them is not too excited about doing so.
They may have been happy in just staying best friends.
However, they decided to go along with it because they feared losing or straining their relationship with that best friend if they were to refuse to date them romantically.
If you reflect on your relationship with this ex who used to be your best friend and come to the realization that they were never truly all that excited to start a romantic relationship with you, this is something that you should strongly consider.
After taking some time from this ex so as to heal from your hurt emotions, it may be best to stay friends with them.
If your relationship with this ex was really good when they were only your best friend, it may be worth it to stay friends with them.
That may have been where the both of you should have stayed all along.
However, on the flip side, without dating each other, you would never have known if you were both romantically compatible.
Now you do.