Am I being selfish?

my childhood friend of 10 years dated my brother at 16. They didn’t ask how I felt about it and it ended shortly after it started. My friend stopped talking to me and started hanging out with new people the same year. It made me very depressed to see my friend and neighbor since I was 6 drop me without second thought for the rest of high school. Fast forward to 2023. I am now 23 and I have been friendly with my ex best friend for while. We have short conversations every now and then and I have forgiven her for high school. Recently, I found out suddenly the my brother and ex friend are dating again. Once again they didn’t care about how it would effect my life or feelings at all. I have not talked to my brother in weeks. Am I being selfish for not wanting to support or have anything to do with their relationship and new life together?

Am I being selfish?
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