Нет, титулы не теряются, просто не используются:Although they will no longer use the "HRH" title, they will not officially be stripped of them, as Prince Harry remains a prince and is still sixth-in-line to the throne. The couple also retain the titles of Duke and Duchess of Sussex, which was bestowed upon Harry by the Queen on the day of their wedding in 2018.https://inews.co.uk/news/uk/is-prince-harry-still-a-prince-change-royal-titles-explained-1369303