Is it obligatory for a young man who committed sodomy and contracted oral herpes to inform the girl of this before marrying her?

Sodomy is a major sin requiring repentance. Repulsive or infectious diseases must be disclosed before marriage. The mentioned disease is infectious and may not be apparent, so it is obligatory to disclose it. If the fiancée accepts, then that is fine; otherwise, he should seek someone else, or treat himself until he is cured, at which point he is no longer obliged to disclose it.