"had to" in itself always (as far as I can think) implies that the verb was realised. "Although I had to say that, I didn't" is therefore illogical. "I thought I had to follow it, but it was not true, so I didn't" is more acceptable because the non-realisation stems from the fact that you thought wrongly, not from any uncertainty in "had to".
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Hans51I had to go there but I couldn'tAgain, it seems contradictory. I wouldn't say that such seemingly contradictory sentences are flat out impossible. It may be sometimes that a writer deliberately wants to give a contradictory impression for effect. However, in normal circumstances you would say it another way (such as using "should have", as previo