Parents opposing love marriage

Hey friends,
I have a big problem in my life. I fell in love with a guy (my colleague) who belongs to a different caste. But he is such a nice guy that I doubt when even my parents look for a guy, they can't find a better person than him. But my parents are so reluctant that they can't get me married to some other caste guy.

But we both earn well and he even settled with a house in foreign land (where we live) though we are still in 25 only. We both are mature and very clear about our life. But my parents are making so much problem. My boyfriend's parents are ok with our relationship. They just keep on asking us when we are going to get married. For now I have calmed down my parents saying that I am away from him and not in touch with him. I have told them that I want to live single and don't want to marry anyone. They are not forcing me to marry anyone nor opposing me (as I have told them that I am not loving him anymore). But how long can I wait like this?

It is already 1 year since I told my parents about my relationship. No development from my parent's side. My boyfriend is so supportive and caring and he is ready to wait for any number of years. But I am so worried as how long I should wait? I am losing my belief that my parents will accept day by day, as they don't start to talk about my marriage please help as what I should do further?