I like the mom's "do as I say, not as I do" attitude about all of this.
The way she talks about her closet being "off limits" sounds kinda sketchy too. The secrecy of it all probably just piqued the kid's curiosity. She's just making it worse by keeping the whole thing shrouded in secrecy.
If the mom is so concerned about the amorality of it all - why does she have all the sex toys?
It also sounds like this is a step-parent relationship - notice the mom says "My husband" not "her father." Sounds like some other issues going on there - "your kid is a filthy perv and I can't deal with it..."