Some interesting readings on the question of whether Peter is an apostate ...

(1) Peter the Apostate?

(2) ROBERT GUNDRY, GAINING RENEWED SUPPORT FROM ETS, DECLARES PETER AN APOSTATE IN MATTHEW’S GOSPEL

 

Robert H. Gundry (currently Scholar-in-Residence at Westmont College in Santa Barbara, California.) also has a new book (Peter -- False Disciple and Apostate according to Saint Matthew) on this issue to be published soon.