I started wife swapping in the Spring.  It started low key.  At first, I would notice she had a new haircut but when I mentioned it, she would give me a funny look and say something like "this old look?"  Then, her wardrobe started getting a tad eclectic.  She is a wonderful woman and very stylish, but even she could barely pull off a full crinoline in a law office.
I started timing the changes.  At first, I would notice one significant change every week or two.  By the time the really big changes were happening, it was at least every day.  Still, I was in denial.  I had no earthly reason to believe that the very fabric of reality was being shredded in my wife's local area.
But then one morning,  I woke up and she was a completely different ethnicity and about a hundred pounds heavier.  And still, I recognized her as my wife.  It must have been Sunday, because we had sex in the morning.  It was such a strange experience.   It ended up being extremely good sex, but I was tormented by a compulsion to break the spell and ask her why she did not notice her transformation.
Obviously, I was psychotic.  I had some kind of break with reality and was living out some sort of perverted fantasy. 
For weeks, I had an intimate encounter with a variation of my wife at least once a week.  Most of the time, it was her but for some small change.  This one has a nose ring, that one got breast implants, that one doesn't shave, this one shaves everything.
Sometimes it was a big change.  She was a lesbian one time and gave me the impression we were mutual beards.  In another, she was a homosexual man.  That was a challenging experience.  My brain still interpreted it as my wife, so I decided to just accept it.  The changes started getting further from any coherent center.
If she just had a gigantic lip plate or an elongated neck or full body tattoo, that was a "normal" day.   She did all of her work from home now.  Does that mean that her coworkers see these changes, too?  She insists that she is just taking advantage of the new remote work policy.  I think that the experience of commuting to Midtown with lotus feet traumatized her.
While I admit a potential breach of ethics: is having sex with alternate universe instantiations of your spouse technically cheating?  Answer: if you think to ask about it, then you already think it is.  I had enjoyed my dalliances, especially with the version of my wife that was a former yoga instructor with a hook up for very good weed.  But now the changes were starting to become concerning.
I had to learn more than I ever thought I would about basic cyborg repair.   Apparently, psychic powers are real.
I hope to one day forget the spider jaws.