Gravity always acts as a pair of forces, not as one single force. The strength of
the forces depends on both masses, not just one of them.
The forces of gravity attract the diver toward the earth and the earth toward the
diver. The forces are equal in both directions. If the diver weighs 150 pounds on
earth, then the earth weighs 150 pounds on the diver.
The diver accelerates toward the center of the earth with an acceleration equal
to (weight)/(diver's mass), and the earth accelerates toward the diver with an
acceleration equal to (weight)/(earth's mass).
Has that helped, or just confused the issue further ?