Title of a thriller movie

First of all, sorry for my English. The movie I'm looking for is 90s/2000s

The protagonist is a ex cop now bodyguard.

He is hired by a wealthy man to protect him (he received some threats).

This man has a son, and the bodyguard begins a relation with his wife.

The bodyguard's mother is killed and he is the main suspect.

SPOILER:

The killer of the mother is the rich man's son. He discovered that the bodyguard is his stepbrother, born after a relation between his father and her who was his secretary.