M: Maid
It started with chastity, then you become your hotwife/hothusband's cuck. Of course, it could never just stay at that. Once you relinquish control like that, let them take away your manhood, your need to serve them only becomes stronger. And, once they know they can make you serve them, they'll use that knowledge. You'd love to serve them sexually, of course, but they've shown no interest -- and you accept that. Instead, you displace your need to serve your hotwife/hothusband to domestic labour. After all, they are the (wo)man of the house, you are their servant. Depending on their tastes, they may even require you to wear a skimpy little maid's outfit -- or maybe not, what's important is that you're doing the domestic labour.
It is how you can continue to feel needed and useful, and you take pride in a spotless house, fresh sheets and an immaculately made bed for them to cuck you on. You even perfected your cooking skills. No greater honour to a cuck than making and serving a gourmet four or five course meal for your hothusband/hotwife and their lover. For their romantic date, before they retreat to that bedroom that you made sure to not only make spotless for them, but also have candles, flowers, and a romantic atmosphere (and, lube and condoms, if they need them, of course). If they're feeling generous, they may leave the bedroom door open so that you can hear every moan, every kiss, every whisper while you clean the kitchen and dining room.
That's when you realise you're no longer just a cuck, but your husband/wife's denied and locked houseboy -- and being cucked is just part of the dynamic.