How to convince parents for intercaste marriage

I am not sure if this is the right sub for this. But I am 26 (F). My parents had been looking for men for an arranged marriage for the past 2 years and I had been fairly open to the idea. I spoke to many people but it did not work out for me. I met a guy about a year ago and we started dating, he's a great boy with a good job. I told my parents about him a few months ago, they are totally opposed to it because he's from a lower caste than us. They have stopped speaking with me and have threatened to lose ties with me. I can't leave my parents but I also love my partner a lot and I think he's the guy for me. Anyone else who has had a similar experience and has been successful in convincing their parents? All suggestions are welcome.