My Fiance Told Me His Families Dark Secretc

So I recently got proposed to, but found out a dark secret the same day. A little bit about my fiance's family. They hate me. They wanted him with a white girl. I'm biracial. They literally said to him in front of me "We wanted the whole thing. You brought us half civilized, half n*g**r". He got so pissed and told his mom to fuck off then. They started yelling at each other and I'm just sitting here awkward ASF. So since then they've been trying to break us up. Tried to even find pretty white girls for him. He has pretty much blocked out his whole family. Tuesday he said he had two big things to tell me. I said what. He pulled out a beautiful ring. I was gonna say yes right away but he said before I answer there's something else he needs to tell me, about his family. He asked did I remember his brother. I said yes. I was not prepared for what he said next. "He's my brother and my cousin". I go "WHAT". Basically his mom fucked her brother. Not a lot of people in the family know who his brothers father is. I was shocked and then another question popped into my head. I asked "Are you an incest baby?" He says " I don't know. My mom REFUSES to tell me who my father is". This was all so much to take in. He put the ring away and said "I'll give you time to think about it". I stopped him and told him of course I still wanted to marry him. He started crying and put the ring on my finger. I love him and he showed he loved me. He cut off his family for me and stood up to his mother. Thing is... She called me uncivilized and she was fucking her brother. If that isn't irony idk what is.

Edit: sorry forgot to mention. Kids aren't really an issue. I had to get hysterectomy a few years back for health related reason. I don't really want children but if we did we would have to adopt.