I am sorry as this must be devestating to you. Politely talking to your dad might be a good idea but you have to make sure that you express your feelings the right way. Don't mention your mother in your plea and focus on letting him know how you felt when you saw the pictures.
Trust me on this. On the surface, your Dad may look contented or not bothered, but deep down I suspect he may be miserable.
It's a creepy life sneaking behind your family/loved ones for away games.
That said, there must have been a void in his family life that he thought would be or expecting to be filled by this extra-marital affair.
Try to remember you are not responsible for your Father's behavior.
Please do keep us posted.
~~Kitt~~Moderator: Anxiety/Panic, Osteoarthritis, GERD/Heartburn and Heart/Cardiovascular Disease. www.healingwell.com"If you can't change the world, change your world"