Lets be practical here,
1)RK(Superstar)
mental abuse- Verbal aggression, Jealous behaviors, Unwedding, psycho phase (his psycho behaviour was after he confirmed if she was still in love with him? Remember studio incident and their dance).
2)Sultan(Gangster)
mental abuse- intimidation, Verbal aggression, Jealous behaviors, Forcing a married woman to divorce her husband, physical
harm to her husband, threatening abt killing her husband, destruction of property, forcing isolation from family.
physical abuse- child abuse, Aggressive behavior, Pointing gun at her, blindfold, forcing himself on her, "inappropriate touching, try to kiss her forcibly" (this comes under sexual assault)
The difference is, if RK mentally abused HIS OWN WIFE at a point, Sultan is Mentally and Physically abusing SOMEONE ELSE'S WIFE aka HIS SIL.