It’s hard to know exactly how your family members will react to the news. Remember that it’s your decision to share this part of yourself with them, and that their reaction is rooted entirely in their beliefs. Try speaking on terms they understand.
Think of the time and place you want to share this information. Consider doing this in private, just so it’s open to whatever emotions start flowing.
Practice the conversation in your head and tell close members of your family (i.e. siblings) first, just so you can figure out the best way to tell your parents. Some families are closer than others, and who you tell really depends on your situation.
Ask them for help or support getting treatment, if you need it.
Mention that it’s hard for you to have the conversation, and that this is you being 100% honest with your family because you’re scared and need their support.
If this STI begins to affect your mental health, you may want to look into speaking with a counselor or therapist. While this option may not work for everyone, talking to a trained professional that understands your experience can help.