I'm pretty sure my dads cheating on my mom??!!?

It was just a normal day. My mom was in England with my grandma and sister. It's a Monday. I get home from school and say "hey dad" he says hay back. I walk over pet my dog and get a snack. "I'm going on the computer I say. (my dads 50) I get on and a Internet tab is open... I click on it... My dads on a conference call. I open the tab and it's and "adult friend finder"... I open it big it's on chat and regular page. The WOMEN on the "friend finder" are 45-53. I was like holy ****!!! But the weird part is that a month earlier my moms on the computer and a PORN tab thing comes up!!! HELP!!! I have photographic evidence of the adult friend finder!!