Last year at NYE a best friend of my SO has betrayed and lied to my SO about suicide. Since then I have never liked the person again and despise them. Ever since March they have been friends again and till this day I do not accept it and get upset the moment I see the person or my SO talks to them.

It has reached the point of my SO gifting them things, talking to them when I had a fight with my SO. They like each other and as a responsible girlfriend I should be glad he has someone that cares about him and makes him happy.

Although, whenever I am tired my lips loosen up. I become sensitive and I get upset easily. I just end up ruining every day for him nowadays with me being upset and after reading things in r/BPDPartners I just feel like a bitch. That I'm just making my SO suffer and I'm not noticing it. 

So I decided it's time for me to shut up.
It's time for me to take my distance and stand on the sidelines. I've hurt my SO more than enough and he deserves better. As much as I want his best friend to suffer a million times more than he made my SO suffer and leave my SO's side forever. 

Of course many people say that bottling up is not good, but I feel like this is the right thing to do.