@D. Fritz
I thought the summary was going to end, "and the son starts to question who is his father?"
Well in my idea, she was already pregnant in most of the videos, and the ones where she wasn't, she looked like someone who had given birth. (Faint stretch marks and whatnot)
Also, why was the mom in the sex tapes? Did she lose a bet? Or did the dad? Was it revenge for something the dad did? Was the dad the cameraman?
The mom is a nymphomaniac who craves sex and enjoys it to the max. Her husband is someone who is really well off, but very very dry in bed and somewhat abusive at times. So basically she's cucking her husband.
Why did she stop, or did she?
Doesn't really stop, just less gangbangs, and more single meetups.
Could also look at who is the father of the son's sister? A different father?
No sister. Just one son. In my early draft of the idea, she was pregnant again but had a miscarriage.