I'm such an idiot

I'm in love with my boyfriends brother. I've been with my boyfriend for 6 years and he's a few years older than me and his brother is my age and I've never really thought about him in any way other than my boyfriends brother until A few months ago. I would wake up multiple nights and realize I was having dreams about him. I'm not really his type and there is absolutely no chance we'd be together because I've been with his brother for so long. Is this normal? I really can't get him out of my head. I'd never have a chance with him I know that for sure but I can't help but wonder what it's like to kiss him.