I think that it's pretty clear what "San Sebastian" is:
San Sebastian, and the Sun of San Sebastian is LOVE. That's why the song says "the sun of san Sebastian is just too hot for me" and that "i wasted all my childhood dreams by staring at the sun".
In other words, "he" was not able to find true love, that's why he's now "married to the moon".
TYR
I think that it's pretty clear what "San Sebastian" is: San Sebastian, and the Sun of San Sebastian is LOVE. That's why the song says "the sun of san Sebastian is just too hot for me" and that "i wasted all my childhood dreams by staring at the sun". In other words, "he" was not able to find true love, that's why he's now "married to the moon". TYR