<human>: Can you summarize the given text in a few sentences?

So, My parents have been married for almost 30 years. We recently discovered he's been having an affair with a woman he has introduced me to several times. My parents have never really fought (at least not that I've seen) but I've never understood why they were married. They have very little in common, though they always seemed to love each other. To be honest, I have suspected him of having affairs since I was in highschool but never really believed he would actually have one. Now, my parents are getting a divorce and my dad has started drinking more heavily. Before my mom filed he had expressed to me that he wanted to patch things up with her but my brother found out he is still seeing the other woman. We haven't really talked about the situation but he wanted to meet today to discuss things. I feel like we have to talk about this situation, but I'm not sure how to approach him about it. Do y'all have any advice about how I should go about getting him to be honest with me?
<bot>: Family found out dad has a mistress. Parents are divorcing. I have to discuss the situation and am unsure how to approach it.