I'm so sorry all of that happened to you. I think you might benefit from sharing your story, or potentially confronting your cousin. It seems like these traumatic events are still shaping your life. You can even share your story online, in the abuse forum, but I think it really would help. Many survivors of abuse find it gets less hard to share the more they tell their story.
I hope this helps and things get better for you.
Also, congrats on being soon-to-be married.
-Sam