I second AnnabelMoore, and would also like to point out that Option 2 is much easier said than done.
Can you abandon a piece of your heart without creating resentment towards your boyfriend? Can you really let go, forget about this other person, and this aspect of yourself that you have discovered?
An impossible option isn't really an option.
Also with Option 3... I really understand the feeling that suicide would "do everyone a favour", but you are obviously loved by at least two people (and no doubt many more... family, friends). Killing yourself may well stop you from hurting people in the future by your actions, but I very much doubt, in fact guarantee with my own life, that there is nothing you could do in the future to hurt them more than how hurt they would be if you killed yourself.
So, I'd cancel option 3 as well.
Leaving you with AnnabelMoore's sage advice.
Another thing: with option 1, there are many possible ways it could go. Perhaps your boyfriend needs monogamy, at least for now. Maybe you can live with that, as long as you can talk about your poly feelings, and work together to see if you will be able to open up in the future (if I'm correct, GalaGirl and her partner are doing this - she blogs here too).
Finally, try to keep the general topic of being poly as a person separate from the specific topic of being in love with this other person. The second would be quite hard to hear, I think, if your boyfriend is mono-minded and has no idea that you have these feelings. Be clear about what you are saying. Are you saying you NEED to be with this other person? Or saying that you NEED to be open about being poly and sometimes having feelings for other people, that don't diminish how you feel about your boyfriend? Whether or not you are able to act on these feelings is a different matter.
Take care out there x