My interpretation is that he was deeply in love with Cherrie and he took a chance to bond with her by doing a crime with her. He later finds out that she has another lover and that she used him to
get the money and to get back at what happened to her when "she took the blame". Not sure if she actually shot him in the chest or was he hurt so badly by love that it felt like he took a bullet in his chest? Hmmm? but then again, there was a gun that slid out of her purse!