This first became a question to me when I was having a discussion/argument with a woman I was in a relationship with.
She was speaking words that didn’t fit the woman that I knew. It took a while to “click” in my mind that I was not just arguing with her, I was arguing with her mother, and her mothers opinions, thoughts, demands and so on were coming through this woman’s mouth.
This is especially harmful to your relationship if she has run back tot he family home to be with her parents/mother giving the mother full access to your love life and relationship.
Her mother and her friends hear all about the breakup as your love tells them it all because she ha faith in them and loves them, but sadly sisters and mothers/parents can have an agenda of their own and cause far more trouble for you both.
If you are having a discussion with the one you love and he or she is nastier than ever before, or says things that they would not normally know, and saying things out of character, then there is a reasonable chance that (even if he or she denies it) they are getting advice from an outside source, possibly even a therapist.
If you realize who the other person is you can reply as if you were discussing/arguing with that other person, or you can try to find a way to get the one who you love to communicate with you without other people’s interference.
The bottom line is that only you two know what really happened because you both were there throughout your relationship, you should be able to fix it up together, if you Both really want to.
Please, just be aware that sometimes other people interfere with your communication with your love one and they can cause a lot of unneeded troublesome interference.
In all discussions with your love, please be mature and understanding.