Ah, so you're asking about the meaning behind the acronym "GG" when used in a romantic context between a guy and a girl. Now, let me preface this by saying that the interpretation of acronyms and slang can vary widely depending on cultural, generational, and even individual contexts.
With that in mind, "GG" could potentially stand for a few things in this scenario. One possibility is that it's shorthand for "Good Game," which is commonly used in online gaming communities to acknowledge a well-played match, regardless of the outcome. However, this usage is typically reserved for gaming contexts and wouldn't make much sense in a romantic interaction.
Another interpretation could be that "GG" is being used as a playful or affectionate term, similar to how some couples might use abbreviations or nicknames for each other. In this case, it might not have a literal meaning and is instead just a way for the guy to express his feelings towards the girl in a cute or quirky way.
Of course, it's also possible that "GG" has a specific meaning that's unique to the individuals involved and not widely recognized outside of their relationship. The best way to find out for sure would be to ask the guy directly what he means by "GG" in this context.