In Japan, the abbreviation NTR is mostly used for Netoru, which is more neutral (third person). It's from this that the terms netorare, netorase, and netori originate.
netoru (寝取る) 寝 to lie down, to sleep (in this case, to have sex), 取 to take, to steal, to assume, to seize, る husband, wife, someone's partner.
To sexually steal someone's (wife or husband).
Genre: The feeling of betrayal, envy, loneliness, abandonment, robbery, and loss, and inferiority, incapacity and sexual incompetence.
Uwaki (浮気) in Japanese, which does not carry with it the idea of theft or loss, of taking, tori (取) from someone else, not the "negative" part of netoru, the partner's betrayal is never discovered, either the partner agrees or both betray and don't care.
Netorare which would mean the act of Netorareru (寝取られる) is the passive form of netoru
Your (wife or husband) is being sexually robbed from you.
netorare does not mean "cuckold," it refers to the act.
Netorareta (Cuckold) a man whose wife has been stolen from him.
Netorase which would mean the act of Netoraseru (寝取らせる)here acting as a cause of your loss.
You and the reason for losing (wife or husband) to someone else.
Netori which would mean the act of Netoreru (寝取れる) If the agent that causes someone's loss.
You sexually steal (wife or husband) from someone.
The abbreviation NTR is used to refer to the verb Netoru without defining a point of view, only the act itself. Therefore, NTRR is used for Netorare and NTL for Netori (due to the sound similarity between Ri and Li), while NTRS is always used for Netorase.