Koichi's personal life is cloaked in secrecy.
My immune system has been weaker than most people's since I was born, so I usually wear a mask when I'm on my own.
Koichi has a lot of stress from work and his personal life is getting messed up. Could you advise him? I believe he needs someone to listen to him.
You've seen 生活 before, right? So what about the "life" of I? Whose life is that? Why, that's my own personal life.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.