Sleeping With the Enemy
As the kids spend more and more time with friends and their own hobbies Marge feels that her kids don't need her as much yet she's got more mothering in her. At the same time Lisa gets picked on at school for being overweight and she decides to go on a crazy diet. Marge then finds an outlet for her mothering through Nelson who never enjoyed any of the comforts in life and after Marge payed him for some house chores Nelson's mother also bails on him which leads Marge to take him in.
Bart isn't too happy about Nelson's move in and after having to deal with his bullying at home and hearing Nelson belt out his rendition of Steisand's "Papa Can You Hear Me" he decided to go out on a hunt for Nelson's dad. At the end Nelson helps Lisa fight off the girls at school who makes fun of her and Bart succeeds in finding Nelson's dad and his mother comes back from Hollywood after landing a role (after only sleeping with the 3 directors!).