Mutant wa ningen no kanojo to kisu ga shitai is a Manga/Manhwa/Manhua in english language, Mature series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.nl fastest updating comic site. The Summary is

The world was devastated by nuclear war and now there are mutants walking about. The story starts with our friend, a mutant who is desperate a girlfriend, but there are no humans left alive, or are there? The mutant meets a human girl and falls in love with her. In a desolate land, a different kind of love burns fiercely, sadly, and purely--!