father
Duncan's grooms, who he and Lady Macbeth have framed for the murder of Duncan. He claims to have been infuriated at their apparent guilt, when in fact he just wanted to shut them up.
"There's no art to find the mind's construction in the face. He was a gentleman on whom I built an absolute trust."
The Creator.
Desdemona
Macbeth is considering the implications of assassinating King Duncan, whom he is loyal to as a subject and kinsman, and also as his host. He questions whether he should betray Duncan's trust and hospitality by committing the murder himself.
father
"Whom" is singular, used to refer to an individual.
Duncan Armstrong's first wife was Nicky Anderson, whom he married in 1995. They later divorced in 2014.
The Creator.
Duncan's grooms, who he and Lady Macbeth have framed for the murder of Duncan. He claims to have been infuriated at their apparent guilt, when in fact he just wanted to shut them up.
"There's no art to find the mind's construction in the face. He was a gentleman on whom I built an absolute trust."
The Creator.
Duncan is a bit miffed with Cawdor because he was a traitor who joined forces with the king of Norway and assisted him in his invasion of Scotland. Naturally, Duncan ordered Cawdor to be executed, musing "he was a gentleman on whom I built and absolute trust."
To whom do you refer please?
"He" refers to King George III
Macbeth claims that he killed the groomsmen out of fury and grief for the murder of King Duncan, whom he believes the groomsmen had conspired against. However, it is widely speculated that Macbeth actually killed them in order to prevent them from revealing his own guilt in the murder of Duncan.