Ok did you ever like a boy you knew you shouldn't like?

the boy i like is my ex's brother!!! i tried not to like him i really really tried but it doesnt work! hes 1 year younger than me........hes strong, AMAZING body has been my best friend for 2 years....well him and my ex were at my house today (dont ask) and my ex kept comming up to me saying "you like him dont you?" i would say no well later that day we were in the basement and devin said "whats wrong?" then my ex said "SHE JUST LIKES YOU?" i turned around like i had been slapped and said "NO I DONT! JUST PLEASE STOP." but when i turned back around i could just feel the tention and im afraid my ex just ruined it ...(my ex still likes me) HELP WHAT DO I DO ABUT MY EX? AND HIS BROTHER?