bioanthro_geek

I'm in kind of a weird predicament and need some advice. Here's the situation: I'm a biological anthro student but my research experience is with a computational biologist/population geneticist. My personal interests are in anthropological genetics and I am applying to programs with that focus. The issue is that my research prof has said more than once that he thinks ecology and evolution is a better field and that I should try and get into an EEB program instead of applying to bioanthro programs. The issue is that I want to stay in anthropology and even though I keep hinting at that, he insists EEB is better. Furthermore, he's said that I could apply to do grad work in his lab through the EEB program, but there's already a genetic anthropologist at the university (albeit, in a different college) that I really, really want to work with and I cannot apply to both programs. I've contacted that anthro prof and he's expressed interest in taking me on as a student recently, but now I don't know how to tell my current research prof that I'm definitely going to be applying through the anthro department and to the other lab without offending or disrespecting him. I'm very nervous about this because I don't want to destroy the relationship that we have or piss him off in any way. So, what do you all think? How should I break it to him?