This dude is so caught up in his own problems, aka his wife cheating and them lying to his father in law, that it seems like he is never going to leave. How much more does Natsumi need to cry before he makes a decision. You can't have it both way, a fake wife and a mistress. Even though your wife is ok with the arrangement because she's using as a cover and you stay because you care about her, Natsumi is not ok, she's clearly in pain and as someone who claims to love her, you should want whats best for her. He needs to either step it up or let her go.
This dude is so caught up in his own problems, aka his wife cheating and them lying to his father in law, that it seems like he is never going to leave. How much more does Natsumi need to cry before he makes a decision. You can't have it both way, a fake wife and a mistress. Even though your wife is ok with the arrangement because she's using as a cover and you stay because you care about her, Natsumi is not ok, she's clearly in pain and as someone who claims to love her, you should want whats best for her. He needs to either step it up or let her go.