I'm sorry, but the way all the salacious details were presented here make me suspect this story is a sexual fantasy. First, dismembership fetish, and then a cuckolding fantasy ("cleanup duty?" hmm), complete with jealousy about "feelings" developing?
I hope I am wrong, but somehow my bs meter is pinging wildly.
If it's true, this couple is using you. It sounds like you are being victimized for the husband's cuck urges, and used by her for your disability.
Love withers under constraint; its very essence is liberty. It is compatible neither with envy, jealousy or fear. It is there most pure, perfect and unlimited when its votaries live in confidence, equality and unreserve. -- Shelley
Mags (poly, F, 60) loving miss pixi (poly, F, 38) since January 2009, living together since 2013
also loving Punk (monogamish, former swinger, 42, M) since Oct 2015
"Master," (mono, 34), miss pixi's Dom for 2 years