The Outsider by E.S. Luck

The world was on fire, and no one could save me but him.

Newly homeless after being forced to abandon their camp by a group of violent cultists, Claire, John, and Kimmy set off on a long, dangerous journey to the one place that they might find safety again: the Valley.
Pursued by the cultists and menaced by raiders and other hazards of the Wasteland, their journey is abruptly cut short when Kimmy is mortally wounded, and the only hope left is also the worst option: a trip back to the ruins of the Cave, the one place where life-saving medicine might still exist. To obtain it, however, they must navigate the compound that the cult now calls home and face the rising threat of its shadowy leader and his twisted obsession with Claire.
As John and Claire traverse a violent, unforgiving post-apocalyptic landscape, the bond between them only deepens, and the fierce passion between them burns brightly. Her desperation for a home and family she can call her own is matched only by John’s determination to protect the woman he loves from a world that seems hellbent on stealing her away from him.

The Outsider is the second book in The Wastelander Series and is the direct sequel to The Wastelander. Like the first book, it is a steamy post-apocalyptic romance that follows John Madigan and Claire Ainsley as they work to build a life together in a post-apocalyptic world. It features tropes like touch her and die, forced proximity, rescue romance, opposites attract, and forbidden love.

Please note: this book ends on a significant cliffhanger.