I was lost at first, because I was expecting a traditional storyline....instead I think this is actually an adult fantasy story. It only makes coherent sense once I realized that the ML is not real. I think he's a figment of each woman's imagination. Each of them seem to be at some sort of crossroads in their life (newly widowed, 1st pregnancy/new mother, Virgin thinking of having sex, crumbling marriage/divorce, etc)...and they obviously are having some sort of anxiety or emotional crisis...and that's when Junichi appears and he basically does whatever that woman desires or in two cases does whatever they need him to do to get them through their issue... usually its sex but not always. I don't even think the sex is real....its a symbol too. The sex is a symbol of their release of tension that comes with the resolution of a stressful/difficult time in their lives. Thinking of the series this way is the only way it makes sense to me....otherwise its just smut.