Why am I Uncomfortable with my cousin BROTHER?

Well, To start, I've a cousin brother who is very friendly and loving towards me. Till a few months before, he maintained a healthy Brotherly relation with me. But Recently, I'm horrified to learn that his Physical attraction towards me and vice-versa is growing unhealthily and that we are often tempted to go to the Dark side (if you know what i mean). I've noticed that he's too interested in physically contacting with me, as well. All are much to my horror because I'm too involved with nhim as a BROTHER and it hurts to think the other way and I'm not comfortabl;e when around him. Any COUNCELLLING, Mates? NEED YOUR HELP.