Complex sentence: They continue to hang out with eachother until she decided to move on in the third-season episode "Moby Dick", which she confirms in fourth-season episode "Citizen Solomon" when confronted by Tommy.
Split into simpler sentences: They continue to hang out with eachother until she decides to move on (third-season episode "Moby Dick"). She confirms in fourth-season episode "Citizen Solomon" when confronted by Tommy.