I think my dad is having an affair with my best friend. Please help?

Wow those are big coincidences. i dnt think you should confront them yet, but i think you have to find a couple more cluess. You should one day ask your friend to let u borrow her phone because ur phone died, and check her txts. or history in calls. you might be able to find something. Or while your dad seems suspicious and going out.. all of a sudden.. try following him . . ask someone to tag along with you for help. you need all the evidence to then confront him about it.