The answer to the question is no it is not cheating. One cannot cheat oneself. All one can do is delude themselves. Further more most developers intentionally bring about the creation of guides. In doing so they have vanquished any expectation that they will go unused. Providing the tool is a validation of its fairness. Technically it does not meet the definition of cheating.
Further more it does not meet the requirements for self deprivation. That depends on which is the greater deprivation. Not defeating a puzzle, or not being able to access the game behind the limitation. There is no right or wrong answer for a no win situation. Which do you prefer, and which is true to yourself. Are you the person that refuses to progress if you cannot do yourself, or are you the person that refuses to not progress.
So technically we have no foul here, but the real question is how does using a guide make you feel about yourself. I do not feel any pangs myself. I use guides as sparingly as possible, and usually in the presence of legitimate reasons to do so. I will not use a guide when reasonable options are available to me, and I will not use guides for perfect completion.
My most common reasons for falling back on a guide. Incomplete or incoherent instructions. Be mindful I will reference the manual thoroughly. Prolonged period of entrapment in a linear environment. Cannot get out, and have been stuck here for hours and have simply run out of ideas. Time sinks or activities that with a massive use of time can be completed, but are just basic mind numbing repetition. Note to others my spatial orientation and mathematical skills are pretty good. My process of elimination is excellent. So when I say massive waste of time it is just that.
Finally I will occasionally use a guide to access other content after completion. Not achievements, but additional quests I might have missed. To me none of this alters the fact that I completed the game, and probably do not want to waste hours trying to trip over things. Just squeezing out a few hours more of content out of a spent game.










