Infiltrate by Nova Noble

Neanderthals return to Earth, this time as modified Neander Beasts, ready to breed humans and take back the planet.
Emily does her best to fend for herself in what’s left of Earth, going to college and working to keep a roof over her head. Her life may not be glamorous, but it’s an honest living. Until one night when a hulking beast of a man kidnaps her from a party and takes her to his spaceship, claiming her as his.
The leader of the breeding team of Neander Beasts sent to repopulate Earth, Crewz has no use for a virgin human female on his ship. Despite his vow to complete his mission to save his species, he’ll have to breed Emily and fight off a rival alien species if he wants to keep his ship.