Please ignore the history of Anarchists fighting the Communists, it simply must have been the dirty Marxists betraying the noble Anarchists.
Are you referring to instances in which Anarchist groups in the Spanish Civil War took actions to hurt Communist groups? I won’t claim it didn’t happen, but I don’t know of examples.
I’m referring to the general distrust of Anarchists by the Communists. They fought against the Anarchists of Russia during the Russian Civil War, yet still supplied the Spanish Anarchists with weapons and vehicles. The general fact that Anarchists struggle with organization and Communists generally don’t to nearly the same degree compounded this.
By what manner do you say the Communists betrayed the Anarchists?
USSR-aligned groups, where they had power in Spain, in many instances used that power to imprison, smear, and seize weapons from, and attack non-USSR-aligned groups. You can look up José Cazorla’s anti-subversion measures in Madrid, or PSUC’s attacks on POUM during the Barcelona May Days.