Red White & Royal Blue by Casey McQuiston

Alex doesn't really like Henry, calls him his archrival and doesn't let go a chance for a verbal banter that sparked during Rio Olympics. The rivalry turns into fake friendship and from fake friends to secret rendevous which are not as easy as you think because Henry happens to be the Prince of England and Alex is the son of the US president.

This is a summary/review. The original work belongs to the Author Casey McQuiston.