Humans having a natural inclination towards the path of least resistance. It is easy to be attracted to him. It isn't the right path to follow, the majority of those that see this as a mistake is because of the word ******. Most societies have prohibitions against ******. It is taboo on many levels. chels you have to resist any attempts to act on any fantasy you have about him. Some one is going to meet and fall in love with you one day and do you want to say you had a Jerry Springer moment with your brother. That dark secret that if they found out would hurt them. good luck and find some one else.
It's because you want to **** him.
Say it out loud to yourself. Then get out and see other people...
You need to get out of the house more. Meet other people. He's your brother not your lover. Wake up!