My mom is cheating on my dad.

The situation is pretty complicated and unpleasant. Recently I have found out that my mom has been cheating on my dad. I haven’t talked to her yet. What I can’t stand about the situation is her presence. I mean she pretends to be a loving wife and caring mother. I bet my dad has no idea what’s going on. And I do love both of them and do not want him to be treated like this.