I'm feeling awkward or angry at my mother for being in a relationship with my uncle
How does their relationship really make you feel?
It is disgusting, they are related by blood, I urge them to stop this relationship for the sake of my family.
It is bad that your relatives are engaging in incest. Incest is immoral and illegal. If they were to have a child it would be disastrous.
I'm not happy that they are in a relationship. I'm not looking forward to seeing them love each other.
It's really taboo indeed, and while love is good, it can't be like this within the family. How about having a serious discussion with the two of them, perhaps you'd be opening their eyes and saving them from disaster.