[njanjayrp]

I dunno. Perhaps you are right. However when you use "aishiteru" it's gender neutral, so she might be referring to someone else. Also the primary difference between using the word "koi" and "ai" is that the former is typically used to express romantic love for one person, while the latter is a more general form of love.

The PVs don't always reflect the actual song though. The song was advertised as a winter ballad and since it's essentially a love song it could have different meanings to different people.

To me the whole arigatou tte part sounds like she isn't speaking about her lover:

I wanted to say "Thank you"
I couldn't say "Thank you"
Because it's like "Good-bye for ever"
And too sad

I think it's more about saying goodbye to someone whose gone, but that's just me. Also Together When... and the whole thing about her being re-born kind of hint she is talking about meeting someone again when she dies.