Why would President Truman be against sharing the secret of the atomic bomb with the world? Why would he support sharing atomic technology with Great Britain and only give minor details to the Soviets, who were also allies?

He didn't want to share the information because no one else had this massive weapon and it was the first of its kind to be made. And most of the info got leaked to the Soviets and Britains by scientists who worked on the bomb, fearing that the US might be too strong with this power.

Explanation:

the berlin blockade was an international crisis that arose from an attempt by the soviet union, in 1948–49, to force the western allied powers (the united states, the united kingdom, and france) to abandon their post-world war ii jurisdictions in west berlin. in march 1948 the allied powers decided to unite their different occupation zones of germany into a single economic unit. in protest, the soviet representative withdrew from the allied control council. coincident with the introduction of a new deutsche mark in west berlin (as throughout west germany), which the soviets regarded as a violation of agreements with the allies, the soviet occupation forces in eastern germany began a blockade of all rail, road, and water communications between berlin and the west. on june 24 the soviets announced that the four-power administration of berlin had ceased and that the allies no longer had any rights there.

when she faked her death and the readers knew but romeo didn't.