My husband is gross and now the dealbreaker?

My husband and I have been married 4 months and together 2 1/2 years. I found out that he lost his virginity to his cousin when he was 14 and she was 12. I don't know how to feel about that... My husband committed incest OMG. I know he was young. A couple of months ago, I found a turd in the shower. It was small, but it freaked me out. I cleaned it up and told my husband. I was worried there was an animal living in our apartment. Then about a week ago, I got home from work and there was poop in the bathtub again when I was trying to give my son a bath. My husband said no it looked like puke and cleaned it up. I told him he needs to tell me what happened because he was the last one to shower. He denied it and lied to my face even when I was telling his mother about the strange occurances. Then he tells me last night that the hot water in the shower gives him uncontrollable diarrhea and it was him. He takes the shower head and blasts it full blast up his a$$. What does he think will happen? And funny, doesn't happen when I shower with him. What am I supposed to think?