Is this morally wrong? Am i going to Hell?

Okay I'm 22 years old and me and my fiance have been dating for sixteen months now. The other day we went to visit her mother, who I had never met, and we found out that we are cousins!!! I love her so much though, she is my entire world. I could never live without her. Plus we already have our firstborn on the way. What should I do?!