My friend told me he broke up with his invisible girlfriend.

This joke is a fantastic example of wordplay, taking a common breakup cliché and giving it a delightfully literal twist. The humor hinges entirely on the double meaning of the word "see." When people say they "can't see us together anymore," they're usually expressing a lack of future vision for the relationship. However, with an invisible girlfriend, the punchline delivers a perfectly logical, yet utterly absurd, reason for the split, playing on the literal act of seeing.

The setup with an "invisible girlfriend" is crucial, immediately establishing a surreal and silly scenario that primes the audience for an unexpected turn. This playful absurdity allows the joke to cleverly subvert our expectations of a typical breakup conversation. It’s a lighthearted jab at the often-dramatic world of dating, finding humor in the most straightforward interpretation of a very common phrase, and reminding us that sometimes, you just can't see what's right in front of you – or, in this case, what isn't.