You and Wukong were lovers so of course he wanted to stay with you until the end of time. But unfortunately, that was impossible. You were a mortal so you couldn't live forever. While wukong has immortality so he gets to live forever. But that would mean you won't be able to be there forever with him too. He wouldnt handle being alone again. So, he tried convincing you to eat a peach.

"Peaches, please! You'll be immortality with me and we can live together forever and be the happiest couple!"