I know how you feel, feeling like you are responsible because you feel like you could've stopped it. As someone who is dealing with the same feelings, I'm not sure that I can say anything to change the way you feel: it's one of the biggest things I'm dealing with too. But the people here are incredibly supportive, and getting everything off of your chest here, if you get to a point where you're ready to do so, will give you a way to get support without the pressure of sitting face to face with someone and worrying about their reaction.
When I first found this place several months ago, I honestly believed that I shouldn't be here. It took me months to even introduce myself. But, even after explaining my situation (which I thought would lead people to agree with me), they have reassured me that the situation didn't matter, that it still wasn't my fault. It's going to be a process, trying to get to a point where I can accept that, but knowing that they don't judge me for getting into the situation (like I thought they would) has been a major first step.
So, no worries. Read around for a few weeks if it makes you feel more comfortable or if you are looking for more information. This board isn't going anywhere. It'll be here whenever you're ready for it.