“Was she always here?”

[Brandnewbuddy]

A long time ago I pitched a similar idea but I wanted to flip it a bit.

Kids come back from college and find their mom having sex with another woman. It’s shocking but right as they are about to confront her, their dad greets them, not surprised his wife is having sex with another woman and just closes the door.

The kids suddenly remember that the other woman is their other mom. Their parents have always been in a polyamorous relationship. But why would they forget something like that?

At dinner, their other mom helps in the kitchen, apologizes for not closing the door, and then along with their parents, talks about all the local gossip.

Kids smile, reminisce over shared memories of the their two moms and dad while subtly trying to catch their parents in a contradiction to prove their other mom has never been there.

That night: kids meet up and discuss their concerns with each other. They quickly text their friends: both local and far away but all of them say they’ve always had two moms and a dad.

As if things weren’t confusing enough, Other mom approaches each of them that night and comes on to them in different ways: for daughter she asks if she found a girlfriend yet, if not she’s happy to teach her all about sapphic love just like she promised before daughter left for college.

To son, she states that since his grades have been doing so well, she talked to his mom about the secret desire he had told her about that summer: and mom is willing to have sex with him whenever he wants.

Both kids tell other mom to leave but they cannot deny how aroused they got around her.

What is going on? Who is this strange woman who never seemed to exist before today yet apparentally alway existed?

OriginallyI was thinking like my old idea, she was a travelling person with psychic powers who rewrote memories so she could hide out in different places, or a succubus.

But then I thought of going sci-fi with it. What if the kids are actually a couple who are playing an erotic VR game that casts them as college kids returning home for taboo debauchery? The other mom was a mod or DLC for the game but the game didn’t finish loading her, which is why their memories of her didn’t load in. For extra fun, the mod creates other glitches in the game (multiple dads spawn in, limbs get lengthened, genitals suddenly stretch out, clipping issues, lol).

 

[Hypoxia]

The easy out: Mama Maria's new lover Lucy is a successful Mad Scientist who's developed a MindControl device or system or whatever, enabling her takeover of the target family. (An author should be able to invent persuasive motives for Lucy's focus on them.) Presto! She's the second Mom!

Drama arises when hunky hubby Hank or just-past-18 twin kids Kelli-Anne and Kenny grow suspicious. What's the giveaway? For fun, when the twins go hot-n-heavy incestuous (with each other and/or daddy Hank), Lucy's spell or device or whatever weakens enough for her dastardly plot to be revealed, unraveling. Now the kids get to double-team mama Maria whilst daddy Hank porks Lucy.

Does this rate a Happy-Ever-After ending?

 

[Thalius]

To me, this sounds a lot like a Succubus fantasy story.

Maybe she snuck into the family to hide from an exorcist?

 

[LupusDei]

That night: kids meet up and discuss their concerns with each other. They quickly text their friends: both local and far away but all of them say they’ve always had two moms and a dad.

To me, that's the hard part that seems intended to exclude most easy intrusion scenarios, magical or otherwise, leading to the necessity of glitch in modded virtual world.

Somewhat comparable, even if convoluted real world scenario could be if the other woman had always been there indeed, and everyone but said kids knew or strongly suspected their parents are living in a threesome, while the kids were held in the dark perceiving the woman just an aunt.

Let's say...

There were two brothers. Martin (the oldest) married a girl, Ellen. Did the girl play with both brothers back then already is open for interpretation. The married brother went MIA. Actual war action or missed at sea, details matter little, what's important that his death is never confirmed.

Folk tradition they live in demands brother to take care of brother's wife in his absence. Sure, it supposedly doesn't imply sexual involvement. What's important it's socially acceptable for the brother to have rather close ongoing relationship with missing brother's wife.

Sally, the girl, Mike, the remaining brother then married, might as well already been third in the ongoing relationship. But, Ellen might not give up hope yet, not for a long time, thus not actually entering possibility of marrying Mike. All while they might fear sexual relationship with brother's wife might be seen as inappropriate by some, not to mention Ellen being promiscuous and bisexual, therefore him marrying their unicorn becomes perfect social disguise. Then, Sally and not Ellen having children follow from there.

Now, keeping the charade up for about or nearly two decades is the hard part. I would introduce a slightly older child (perhaps a daughter) of Ellen, who is labeled as cousin to our POV siblings, but might as well be a half sister -- and it's important in this case that is open for interpretation, perhaps officially she's conceived, like, the very last time Ellen and Martin were together, and born already after his death/disappearance. The three are raised pretty much together, and taking care of her is the socially acceptable anchor for keeping the brother's wife around.

Ellen didn't live in with Mike and Sally full time even though visiting often and for extended periods (and her daughter far even more, perhaps), but nominally had her own place. From the children perspective aunt Ellen had a separate household, only remotely supported by their dad. With didn't feel weird, because it was always been so. Their immediate parents were a happy couple, and children are routinely blind to parent's sexual shenanigans, and so the ongoing threesome with "aunt" Ellen was hidden in plain sight. Less naive more distant observers had strong suspicions, but it was kept low key enough to not garner too much rumor.

Now what changed? First, with children out to college, there's no need to hide anymore. Second, it could finally be long enough for Ellen to accept her loss. There might even been proof of Martin's death unearthed. Or simply, the threesome had found new heat in their relationship, and stopped carrying for appearances (with again could be at least partially traced to children being old enough to not be too adversely affected by having non-traditional family).

Either way, when the children start phoning around asking what "aunt" Ellen is their lives, no one has a lot of resistance to accept she's their other mom on first suggestion.

 

[DCO_65]

When I was (this is Literotica, so let's say eighteen) I discovered that while her children-- whom I knew as my cousins-- were my biological relations, the woman that I knew as my "Aunt Anne" was not. She had been a close friend of my mother and father from their youth whom they never let drift away. As teenagers, both dad and Anne's intended were sent to Europe to fight the Nazis. But only one returned.

Scientifically it's all probability. DNA tests show that there is an overlap at the upper end of first cousins and lower end of half-siblings. But mom, dad, Aunt Anne, and eventually all of us knew.