First thing that comes to mind is NTR.
There are 2 types of NTR.
First: Netorare
Second: Netori
The first one is you getting cucked.
The second one is you cucking someone else.
These also apply to characters, i.e. protagonists of novels/manga/anime etc.
In most cases when some uses NTR they mean the first one, and not the second one. If the mean second one they usually mention it.
If you like NTR (1st) then you are literally the shittiest creature alive.