Coupled sims not sleeping in same bed "this is _____'s bed!"

For a while now, whenever I have two sims in a romantic relationship, whether it be married or just dating. One of them refuses to stay in bed and sleep. I have tried to just buy a new bed but that also doesn't work. I'll go to press "Sleep" and text pops up above the button "This is ______'s bed!" Insinuating the bed only belongs to one of the couple. I have to tell them to sleep 2-3 times, each time they get completely out of bed, before they'll sleep through the night. I saw a couple of posts saying something similar but none of them mentioned the text so I decided to make a post. I don't play with any mods so it's not an issue there.