Knowing that someone is trans does not give you permission to disclose that information to other people. A detail shared on a date, in a message or in one online setting may not be something the person wants repeated elsewhere. Ask about the audience instead of assuming that information is either universally secret or universally public.
Check what you plan to say
Before an introduction, tell your partner who will be there and ask how they want to be introduced. “This is Alex, my partner” may be all that is needed. Do not add identity history to explain their appearance, name or relationship to you.
If you want to tell a friend about a date, describe your own experience without treating the other person's trans identity as the story's defining detail. You can say that you enjoyed a conversation about music without sharing information the person has not authorised you to repeat.
Treat permission as specific
Permission to tell one friend is not permission to tell a family group, a colleague or an online audience. Ask again when the audience or purpose changes. A person may also want to make their own introduction rather than having you speak for them.
For example: “Would you like me to say anything about your identity before the visit, or should I simply introduce you by name?” Accept the answer without requiring a justification. Do not describe your curiosity or convenience as a reason you need to disclose more.
Notice indirect disclosure
A photograph, event tag or comment can supply context even without an explicit label. Before posting a picture together, ask about both the image and the accompanying description. Avoid sharing a previous name, old photograph or private message as background for an otherwise ordinary update.
Do not ask mutual acquaintances to confirm someone's history. If a practical question remains relevant to a plan, ask the person directly and leave room for a limited answer. You are not entitled to assemble information from other people because a conversation did not satisfy your curiosity.
Respond honestly if you shared too much
Name what you disclosed and to whom. Remove material you control and ask recipients not to repeat it, without promising that every copy or memory can be erased. Ask what the affected person wants from you next rather than announcing a public apology that reveals the information again.
The person may change what they share with you or choose to end contact. An apology does not require them to reassure you. Future care means respecting the actual audience choices they make, not deciding for them what should remain private.
Further reading
Trans Journalists Association: Stylebook and Coverage Guide discusses disclosure and self-identification in reporting. The dating scenarios here are editorial applications, not legal guidance or source-endorsed scripts.