Maybe what happened was that you were inclined to kept working as hard despite the advantage of the draft he was providing (while he maintained his effort, but lacked the advantage your draft had recently given him), so it just seemed like he intentionally slowed down in front of you. Add the fact that the guy smelled and suddenly the effort required to get and stay ahead of him (rather than drop back and remain effectively downwind) became inconsequential.
In any event, I can just imagine what it was like, and it sure seems like fun; good story!