An apology can name an action, acknowledge its effect and explain what you will do differently. It cannot require the other person to forgive you, reassure you or resume the relationship. Start with the specific mistake rather than a defence of your overall character.
Name what you did plainly
“I shared your message with a friend without asking” identifies the action. “I am sorry if you were upset” leaves the action unclear and makes the other person's reaction sound like the main problem. Use a description you can take responsibility for without adding a counter-accusation.
If you used the wrong name or wording for a partner, correct it without asking them to comfort you about the mistake. You can say, “I used the wrong name. I am sorry; I will use the name you asked me to use.” Keep attention on the correction rather than an account of how difficult you find it.
Acknowledge what you actually know
You can recognise that sharing a message removed the person's choice about its audience. Do not claim to know every feeling it caused. If they choose to explain the effect, listen without disputing whether they should feel that way.
An explanation may be relevant, but it should not cancel responsibility. “I thought my friend could help” does not replace “I should have asked you first.” Avoid asking the person to approve your intentions before you address the action.
Offer a concrete repair within your control
For the shared-message example, you might stop sharing, remove your own forwarded copy and ask the recipient to delete theirs. Be honest that you cannot guarantee deletion from someone else's device. Ask whether there is another practical step the affected person wants, without making them responsible for designing your entire response.
Do not substitute an expensive gift or a public gesture for a requested private correction. Ask before involving other people. A public apology can itself reveal information the person wanted kept private.
Follow through without demanding closure
State the future action clearly: “I will ask before sharing any part of our conversations.” Then act on it. Repeatedly asking whether you are forgiven can turn your apology into another request the person has to manage.
They may need time, set a different limit or choose not to continue the relationship. An apology remains appropriate even when it does not produce the outcome you want. Repair is about the actions you can take, not a promise that everything returns to how it was.
Further reading
Love is respect: personal boundaries. These apology examples are editorial suggestions, not clinical guidance or guarantees of forgiveness.