telling my bf I want to move 5000 miles away

I need help girls I have been offered a job 5000 miles away from where I live now and I'm really considering taking it but me and my boyfriend have been together for coming up four year and there is no way he can come with me. I haven't told him about it yet because I don't know if I want to leave him but this job could give me a career that would set me up for life and it's my dream job what should I do???