Depends on what you call acceptable. The Beatles made a career out of stepping just outside of the lines. If you're truly in E major then you're only "legal" major chords would be E, A, and B, but F# major wouldn't be far out of line if you went from F# to B then E to resolve the end of a phrase. You may have slipped into a mode that makes these chords sound friendly to your ear, but to answer your question...no, it wouldn't fly from a theory point of view. YMMV
Legal chords in E major:
E, F#m, G#m, A, B, C#m.D#dim, E