That's a fallacy because I'm not assuming that your choices are flawed, lack legitimacy or seriousness because they're different from mine.
In fact, I'm not criticizing you at all.
I'm stating quite clearly that this idea that things like "dating" and "seeing each other" are different from each other, and that one could be seen as more "serious" then another as a general rule, is ridiculous. For all intents and purposes, those statements are synonymous.
That's fine. Stick to your levels system or whatever you want. To me, it's overly complicated for such a simple thing as defining a relationship, but if you like it, go for it.
The only real thing that matters is this: Exclusive, yes or no? Because if one person thinks it's an exclusive relationship and the other doesn't, that's a recipe for disaster, and someone's feelings are going to get very hurt.
And to complete that thought, if the man you're dating doesn't know your level system and where your relationship is on it, you're going to want to be clear on precisely where he stands on the exclusivity level if you want to avoid a problem.