What is the word for a secret concerning one’s own life?

The following passage is found in The Luminaries by Eleanor Catton:

... there is a great deal of difference between keeping one’s own secret, and keeping a secret for another soul; so much so that I wish we had two words, that is, a word for a secret of one’s own making, and a word for a secret that one did not make, and perhaps did not wish for, but has chosen to keep, all the same.

Notwithstanding the speaker’s befuddlement, there is a word for a secret thrust upon you - confidence

(often confidences) A secret or private matter told to someone under a condition of trust: the girls exchanged confidences about their parents

But is there a discrete word for a secret of one’s own?

Solution 1:

The only thing I can think of is personal secret, but that's a descriptive combination rather than a precise term.

Solution 2:

The best I can think of is what we call in France jardin secret [=secret garden].

It could be rendered into English as one's own little secret or one's private world.

E.g. a famous lawyer spends all his weekends reading Ancient Greek poetry, and no one knows it except his wife and closest friends. He'd say: "C'est mon jardin secret" [=It's my secret garden].

Solution 3:

Skeletons in one's closet comes to mind.

It was my first date with this girl. I daren't tell her about the skeletons in my closet, I didn't want to put her off.

Solution 4:

I can't find a single word either. I congratulate you on finding yours.

The only words I can offer is that if it's solely a personal secret, it must be undisclosed or unrevealed.