Just found out my dad is having an affair, don't know what to do. I have had suspicions for a while so I checked his phone and sure enough there was a number of messages confirming this.

Clearly this has made me fairly angry, I just can't decide what to do. My parents marriage lacks love and compassion so maybe it has been coming.

I don't know whether to confront him, tell my mum, tell my sister or possibly even some of my parents friends I know well.
Any help and advice would be greatly appreciated.