Am I just a backup?

I was in a relationship with one of my colleagues for 2 years. I supported him financially and in his career, always putting him as a priority. Four months ago, I got a great opportunity at another organization and moved there. He was very happy about it at first. After I moved, he went on a trip with his friends, and his behavior started changing. He began ignoring my calls and messages. Eventually, he revealed that he proposed to his female best friend and wants to be with her. When I asked for reasons, he told me that our caste is different and my salary is higher than his. He said he forgets his problems when he is with her, while I have been trying to help him with his issues. Despite this, he still wants to be friends with me and shares every problem he is facing.