The father of my boyfriends nephew molested me as a child, am I wrong for not wanting to be around this baby?

I found out last year who molested me as a child, that man is also dating and now has my boyfriends sister pregnant. We told her about him over a year ago when we pieced it all together. She stayed, is pregnant and doesn't seem to even care. I chose not to go to the baby shower, his sister knows why and was understanding. But I want nothing to do with this new baby, my boyfriend is understanding but thinks I'm wrong for not wanting a relationship with the baby, as it's not the baby's fault.