Primary and secondary waves are body waves, and Love waves are surface waves.
Seismic waves by definition are waves of energy produced by the abrupt contact between the rock and the earth or it may be caused by an explosion.
Seismic waves can be divided between body waves, which move throughout the internal layers of the Earth, and surface waves, which can only move along the superficial parts of the Earth.
Primary waves travel through solid rock and fluids whereas the secondary waves only through solid rock.This is the reason why they are body waves.
On the other hand, Love waves move the earth from one side to the other.This is why they are surface waves.