She broke into Dad's iPad and found his mistress

DEAR ABBY: I had suspicions my dad was cheating on my mom, and when she found a mysterious earring in the house one day, I knew I had to find the proof. I went into his iPad and checked his email/Facebook and IMs, and found he apparently has a girlfriend. She works in his office and is also married with a family.

Dad found out I broke into his iPad and confronted me. Instead of apologizing for cheating on my mom, he told me I need to think about what I'm doing because I could be ruining a bunch of lives. He also made sure to tell me that by breaking into his iPad, I had broken the law.

I think I should tell my mom because she doesn't deserve this, but I'm not sure how to tell her.

- Found the Proof in Georgia

DEAR FOUND THE PROOF: There is a saying, "The best defense is a good offense." That's the playbook your father is following by trying to make you feel guilty for his transgression.

Because your mother found another woman's jewelry in her home, she may already have a hunch that something is wrong. Tell your mother what you have discovered, because her marriage is threatened and she deserves to know so she can decide how she wants to handle it. Forewarned is forearmed.

DEAR ABBY: My husband, "Evan," and my mother do not get along. When our second child was born, Mom came to help out, and she and Evan engaged in tense conversations concerning politics and religion. Two days after my arrival home with the baby, they had a huge argument and Mom walked out. She has never returned to our home.

I can't control either person, so what suggestions do you have to repair the relationship so I can have family holidays and get-togethers again?

- In the Middle in Colorado

DEAR IN THE MIDDLE: Much as you might wish differently, the only people who can fix this are the two of them. If they were more mature, they would, in the name of family harmony, agree to disagree.