Help!! My brother is ruining my life?

I don't know what to do, me and my brother have worked together in the evening for about a year now and we both still live at home however i am hoping to move out soon cos i am just getting so fed up with him. He's 35 and i'm 27. The thing is a guy started at work about 7 months ago and since then me and him have got on really well. We've been out a few times as friends but i have developed strong feelings for him and i am getting the feeling he likes me too. But my brother just hates it! He is the most jealous person i have ever known, he can be spiteful and vindictive. Because he hasn't got any friends or girlfriend he won't let me either. I am worried that he is going to say something to my guy friend and turn him against me. If i talk to him he might go and have it out with my brother but then my brother's said if he ever did he'd have us all out of a job. What can i do, it's so difficult cos i get it at home and work and it really makes me upset. Sorry for this being long!