My husband is racist

My husband and I have been married for five years We have two boys together, 4 and 1 years old. He has always been a great man and I'm shocked to notice he's starting to be so racist. He owns a company with his best friend who is Muslim. Our families are like one, our kids are like brothers and sisters. Yet he says horrible things, like how he thinks that "race traitors should be killed". I have only been in one relationship before him, that man's grandparents came from Syria, so when I heard my husband say that the first time I confronted him and said "well then you want me dead" and then he confessed he's struggling with the thought that I have been with a man from a different race. It made me so angry and hurt. Why the hell does that matter and why would he even marry me then?! I'm so scared and hurt and pissed off at myself that it's been so long and I never noticed. I've told him he needs to change his ways because I don't want my children to grow up with his views. I don't know what to do. I love him so much, but this isn't okay. He promised not to say such things in front of our children, but I don't think that will help. I guess couples counselling won't make him any less racist either. He says he loves me, but how can I be with a man who believes in everything I don't? He treats people well, always. He just talks like this at home with me. I can't believe this is actually his opinion. But it hurts me every time and I don't think I can live with it. I would hate myself and feel like a failure if our boys grew up to be racist as well. I don't know what to do. I guess racism isn't a valid reason for me to get custody of the children either, which makes me afraid of leaving, because now at least I have control over what's being said and done in their presence.