Is your own clone fucking your girl with you NTR? Let's approach this from a logical-mathematical perspective.
First, let's establish some kind of base equation. We need to conclude the relation between fucking your own clone and masturbation. IF masturbation is "fucking yourself" and your clone is "yourself", then by pure equation we conclude that "fucking yourself" is "masturbation".
Now let's apply this logic to the context of "is fucking yourself gay". Masturbation, by all means, is not considered gay - it's your own dick, and that doesn't count. Biology made your own two balls touch by default. Ergo, fucking yourself, which is "masturbation" is not gay either.
NOW, we can apply an identical formula as above to the idea of you and your clone fucking your girl:
IF you x clone sex ≠ gay THEN you x clone x girl sex ≠ NTR, since the "clone" is considered yourself, so the formula is more like (you x you) x girl.
Therefore, philosophically speaking, it is NOT cucking if you and your clone fuck your girl. Please note the above formula works only when the scenario of "you WITH your clone" is kept intact, as "your clone fucking your girl while you are not" is an entirely different context.
Thank you for coming to my TED talk.