Years Apart

As a seventeen year old, myself and two other trainees were invited into a house by the home owners wife, when we were landscaping their back garden.
All three of us had her sucking on our cocks before we took turns fucking her pussy and arsehole.
Over the three days we attended the house, we all continued to fuck her, but I fucked her the most having the biggest cock.
Eleven years later, I'm now fucking her daughter, yet didn't know she was her daughter until recently.
When we met, we both recognised each other, but obviously said nothing.
Her husband has long been kicked into touch, as he couldn't cope with her constant sex drive.
On our second meeting my girlfriend popped out, leaving us alone supposedly for only a few minutes, but was gone an hour.
In that time I had my dick sucked, licked out my girlfriends mums pussy and arsehole making her orgasm multipletimes, and fucked both holes too, cumming twice inside of her.
When my girlfriend got back, she acted like nothing had gone on, but you could smell sex all over the house.
Later on back at mine with no chance to shower, my girlfriend sucked my dick and went crazy for my cock up her arsehole like never before.
She'd never been that turned on and I swear it was because of her mums essence on my dick.
Now when we visit, my girlfriend always makes an excuse to leave us alone for a while, and her mother and I fuck like animals.
When we get back to my place, it's always the same, really rough ferocious sex and she never fails to cum so intensely.
I'm beginning to think, they're both using me for sex, and probably tell each other everything.
I'm not complaining, I'd just wish they'd let me know so I can fuck them together.