My situation is complicated. I need some input.

[Lucky SC]

def tell everyone man.

no offense towards you, but if you can't be up front with them... then you can't expect others to do the same. As someone said before most would probably get the thought in their heads you are trying to get close to guys by joining a fraternity which are historically heterosexual organizations.

Like i said you can't expect someone to make the first move of maturity, you have to tell everyone the truth about you, only through honesty can you really make people understand and hopefully in time accept you for being the person you really are

[SWTXBelle]

You said you joined as a sophomore a year and a half ago - how much longer do you have in school? I know everyone may not agree, but it you are only going to be active 4 more months it might not be worth the drama to come out. It depends on how much of a burden not telling would be. If you are going to be busy with classes and graduate stuff, the fraternity might not be as big of a problem as it has been in the past. Your call, of course.
If you have more than the one semester, you should most certainly tell - but you might want to talk to your advisor first. Maybe you could plan to come out (at a chapter meeting? informal meeting? - I think telling everyone at once might be the way to go) and have the advisor ready to discuss the situation with anyone who might have a problem. I would hope your brothers would be able to handle the truth manfully and in a mature fashion. Ultimately, they should focus on you as a person, and not as a sexual orientation. Everyone is giving good advice - think long and hard, and I am sure you will see the right thing to do. Best of luck, and I hope everything works out for you.