Step father doesnt like me.. What do I do?

I've been with this girl for a year now and her dad dislike me when I say dislike I mean hr hates me and it not even funny.. He told her to break up with me but she told him no we really love eachother and he said he is not going to stop until we break up.. Im not scared of him I dont say hi to him he told her not to say hi to him until the relationship is over so she doesnt say hi to him. He told her that he is going to something to break us up and that something remain a mistery soo I really dont know what to do with him. Anyone have good avice for me dont tell me to break up with her because I wont sooo what would you do in this situation?