I don't want to be with baby daddy

Baby daddy and I were never in a committed relationship. After our last weekend together, we didn't speak again until I found out I was pregnant 3 weeks later. Baby was completely unplanned and a complete shock. Now, after giving him a fair chance, I really don't want to be with him. Anyone in a similar situation? I don't know how to tell him. And more importantly, I don't know how to tell my Aunt who is very Mormon that not only am I pregnant, but I also don't want to be with the father. My aunt is more like my mom. I practically live in fear of her. Any advice appreciated. Thanks!!