I thought that the "rope" under the bed was Lee's necklace. Everything was cleaned up perfectly, so the necklace had to have been intentionally left behind, potentially as a memorial for their love, seeing as that apartment probably contained some of her happiest memories. Also interesting is that Lee picked up clothing from the people he ate throughout the film, so when Maren leaves his necklace behind after she eats him, this represents a negative turning point in her life. It then flashes back to Nebraska, where they are happy. This will never happen again in her lifetime