There is a lot to unpack with this one and it’s ice-cold on both sides. Ultimately, I’d tend to agree that this dejected twin is NTA for his actions. He has experienced a lot of hurt and expected his twin sister to stand by his side. 

Typically, when someone cheats and betrays someone on this level, you would hope that others would take a second look at their relationships with that person and reevaluate. Yeah, it sucks for the twin sister to have to lose a friend but she should lose that friend over this. That person betrayed someone that she shared a womb with. It should be goodbye. Adios. No second chances. 

I can understand that feeling of betrayal and what this guy must have felt when he saw that photo. His actions are ice-cold but well within reason.

It’s always terrible to see rifts like this grow between siblings. Take these sisters who had a falling out when the elder sister wouldn’t pay for her younger sister’s grad school.