S17E03 Milhouse of Sand and Fog
When Maggie gets chicken pox, Flanders tells Homer to create a pox party at the Simpson's house. But, Milhouse then finds Kirk and Luann kissing on Marge and Homer's bed. Milhouse is excited that his parents are back together, but kind of not when they're not paying any attention to him and tries to break them up with Bart. The results end up disastrous as it breaks up Homer and Marge too and then, when Bart ends up doing something, the only thing that matters to Homer and Marge is each other.