This is hypothetical:
You're single.
You meet a lovely charming man.
He is kind to you, attractive to you and a real gent.
No one has been so kind.
He helps you when you need it.
He gets on with your friends.
He treats you.
The conversation is stimulating.
He defends you.
He is a nice person to you and you feel special.
You spend time together and over time are in a relationship.
You find out off someone else that he is racist.
You've seen no evidence of this before and no conversations have led down this road.
You investigate either by speaking directly to him or by other means and discover that not only is he racist but he is high profile in a racist organisation.
You discover he has committed violent racist acts and treats others of a different race in complete contrast to the way he treats you and makes you feel.
You love him.
He is racist.
What would you do?
Please note that I have not referenced any specific race here.