The Emiratis are withdrawing their forces from Yemen, a recognition that a grinding war that has killed thousands of civilians and turned Yemen into a humanitarian disaster is no longer winnable. What will Saudi do? via
I suspect the UAE withdrawal is partly driven by their greater awareness (compared to the Saudis) of just how toxic the Yemen war has become in the US, esp. among Dems. With the 2020 election approaching, UAE may be trying to cover their political flank.
U.A.E. Pulls Most Forces From Yemen in Blow to Saudi War Effort