Acting on a tip off, Mohammed Imran was arrested after a trap was laid in suburban Andheri, an officer at Vile Parle police station said.
According to police, the victim Shivchandra Sharma was brought to V N Desai hospital on Monday with grievous stab wounds.
During the probe, the investigators learnt that Sharma maintained an affair with Imran's step-mother, who was married his father Mohammed Aamin Khan.
Imran was furious that Sharma had been maintaining the affair with his step-mother. He called the victim to the building in Vile Parle where he was working as a watchman on Monday and assaulted Sharma with a sharp object, police said.
