First, I'm so sorry to hear about what you've gone through. Your first boyfriend was a monster, and what he did was unforgivable.
You were strong enough to move on from that, but your strength was rewarded by two more bad relationships with two more bad guys. And for that, I'm sorry as well.
I don't know enough to say if you are doing something to attract these terrible guys. I don't think you are, because the third guy was in the same circle of friends. All of this could just be terrible, terrible luck.
That said, there are places in the world where good, friendly, honest, kind men are. I suggest go finding those places. Church groups (if you're the religious sort), or volunteer organizations, or even in your circle of friends. There are many more good guys than bad guys in the world. You're bound to come across one if you keep your hopes up and keep looking in the right places.
Ladies, what else can our friend do to stop this pattern?