If you're getting enough air breathing every 3rd stroke, that's fine. My only advice is you don't have to make breathing on both weaker and stronger sides a priority over getting enough air. I breathe off my right shoulder 80%, left shoulder 20% and when necessary (chop, swimmer piranha, or just can't breathe off right shoulder). But I do feel comfy with 2,2,4 - 2,2,4 breathing pattern and get more than enough air with swimming open water. Often I'll breathe on 1's if I miss enough air off my right shoulder, i.e. breathe right shoulder, then breath off left shoulder on next stroke.
In any case, don't let a pattern or breathing on weak side compromise getting enough air to swim whatever distance happens to be your goal.