Gus wants Jesse to cook alone, so he gives Walt a permanent ultimatum.
Breaking Bad – Season 4, Episode 11: “Crawl Space”

Gus wants Jesse to cook alone, so he gives Walt a permanent ultimatum.
Jesse and Mike work more together. Walt and Skyler's relationship changes drastically.
Walt and Skyler have to come together to sell their lies to Hank, when Walt finds out his brother-in-law is helping on a new case.
Skyler offers to pay for Hank's medical bills. Walt and Gus meet alone to discuss current events.