It's a circadian rhythm thing. You get into a habit of peeing at specific times, and that can include in the middle of the night. You can fix the habit by wait

It's a circadian rhythm thing. You get into a habit of peeing at specific times, and that can include in the middle of the night. You can fix the habit by waiting a half hour longer to pee each night until you can make it to the morning, but this does involve lying awake in bed for a while, which is much worse for your sleep than just getting up quickly to pee.