Newton's Third Law of Motion says:
"For every action, there is an equal, opposite reaction."
(That wasn't Newton's exact words, but it gets the point across.)
Forces always act in PAIRS. The two forces of the pair pair always act in opposite directions, and their strengths are always equal.
The force of Gravity is always a PAIR of forces. The two forces pull in opposite directions, and their strengths are equal.
If the Earth pulls the apple down with a force of 1.5 N, the apple pulls the Earth up with a force of 1.5 N.
Whatever you weigh on Earth, the Earth has the same weight on you !