Forever
Explanation
The Joke
A woman tells a man "Baby, I will love you forever." The man (revealed to be a green-skinned alien) panics, saying he is not ready for that kind of commitment. When the woman protests that he said he would never leave her, the alien explains that humans do not live forever like Zorblaxians -- so a human lifespan is just a "rest-of-your-life fling" for him. When she says he said his heart belonged to her, he notes that Zorblaxians have 57 hearts. Finally, she asks if he looks at pictures of "Zorblaxian procreation claspers" when she is not around, and he deflects with "Don't ask questions you don't want answered, Cheryl."
The Humor
The comic takes standard romantic declarations and makes them absurd by applying them to an interspecies relationship with an alien. Every romantic cliche falls apart when examined through the lens of alien biology: "forever" is terrifyingly literal for an immortal being, "my heart belongs to you" is less meaningful when you have 57 of them, and fidelity becomes complicated when your species has entirely different reproductive anatomy. The escalating reveals follow classic joke structure, with each panel undercutting a new romantic trope. The final panel is the funniest because it shifts from the alien debunking romance to him being caught in a very human-seeming guilty dodge -- suggesting that despite his alien nature, he is still a typical evasive partner.