Hey buddy, you're not broken, you are traumatized.
Well put. I don't want to refer to you as broken because of this quote.
Welcome to malesurvivor. You'll find lots of help here. On this site you have the three greatest assets you could ever have to help you through this. First and foremost, you have yourself and your drive to get better. Second you have plenty of trained professionals that have studied these issues for years, and last, but most definitely not least, you have the survivors that are experienced in these topics because they've been there done that and bought the tee shirt.
First off, what you just wrote showed a lot of courage. Recovery takes a lot of courage. You have it! That is a good sign. It sounds as if you have a lot of issues to resolve around this horrible incident. First and foremost, it's important to speak to a therapist. Sometimes we connect with our therapist, sometimes we don't. It's important to shop around and find one that you can trust and feel comfortable with.
Second, it was not your fault. Once again, IT WAS NOT YOUR FAULT. You made a choice. Death, or abuse. A shitty choice to be stuck with indeed. However, you weren't aware of the effects that the incident would cause. Your natural instincts told you to do whatever it would take to survive. Sometimes we all wish we were that badass that would take the guy out. Unfortunately, the cookie doesn't always crumble that way. I'm sure this guy was experienced with this. At least your still around to get well.
In recovery, there is also a lot you will learn about sexual orientation. I once had the same fears around that as you did. Becoming erect and ejaculating doesn't always occur because the person wants it to. The body reacts to certain stimulants the same regardless of whether or not that stimulus is warranted or not. Also, if you get time, take a look at this. http://en.wikipedia.org/wiki/Kinsey_Reports
This is pretty basic info. Feel free to browse around and look more into it. Learning this helped me somewhat.
Good luck my friend. Your walking down a dark road right now. The lamp in your hand only illuminates a couple of feet in front of you. However, for the time being, a few feet in front of you is all you need to see.