how do you tell somebody that you have fallen for them, when you know it cannot happen? Here is my situation:

I was apart of a group consisting of 5 guys and 9 girls. I ended up finding one of my friends interesting so i started dating her. We went out for about 4 months before i found out that she cheated on me over the summer. She failed to mention it to people that she cheated becuase she didnt want to look a certain way apparently. It hurts cause you think that you arent good enough for somebody so they need someone else. Now, im not he type of guy that goes around and tells poeple why my relationships don't work so i never told anybody about her cheating. First semester of sophmore year i hook up with a few different people, but nothing to serious just because i haven't found anybody interesting enough to be my girl friend. I pretty much drop that group of friends because i just cant be near her and since she never told anybody, they seemed to believe that she was right int he situation.
So second semester starts and i met this girl who is into me. I think i like her so we chill acouple of times and hook up. I start hanging out with my old group of friends from last year, which includes my ex, and finally feel that i am ready for a relationship again. I realize now that my friends care about me so thats why i kinda go back. It doesnt take long, but i start to have feelings for this one girl. Its not like we know each other amazingly, but i just cant seem to stop thinking about her. Shes hot (the hottest girl in this group), smart, funny and a real caring individual. It turns out that her and her boy friend broke up and i was there to help her through it, cause i had just recently gone through it.
The question im asking is this. My group of friends are very protective and i feel that if i were to tell Jenna how i feel, that the group wont let it happen a) becuase they see how me and my ex act aroudn each other, b) they dont want to see the group break up, c) cause half of these girls would think that this was not a healthy relationhship. Ive tried to ignore my feelings becuase for some weird reason, i dont think it would work out. But as you all now, the heart wnats what the heart wants.

Now, i know all of you are going to tell me to tell everyone about my ex. Thats not going to happen just because i dont want that to get out there. But what should i do about Jenna. Should i just try and ignore it till it gets away or should i step up to the plate and try to do more.

I also think im afraid of rejection, so that plays alot on my mind.