I know this is directed at women, but I feel compelled to answer it anyways. I am married to my best friend. Love is more than just sex, it is a deep and abiding friendship with your partner. I find it sad that too often people focus on the chemistry and sex when there is so much more to a relationship. I courted my wife for 2 years before we were married (and we never had sex in that time) and we have since been married for 2.5 years. We have never run out of things to talk about. We are best friends. All aspects of our life is great from the friendship part to the bedroom part. We respect each other and enjoy spending hours together.
My point is that if you are interested in a deep and committed relationship with your friend then you should go for it if you think he is as well. If on the other hand you just want sex then don't jeopardize a good relationship over something superficial like that.