It's "Weta" by mcparrot. Sorry I don't have the link, but the author can be found on both lj and fanfiction.net
Yep, that's mine. (Yay - happy dance - thank you for liking my story.)
It's on FF.net (which really surprises me because I thought it was on LJ too - but apparently not)
Summary: An attack by an insectoid alien causes Jack great distress and causes one of his deepest secrets to be revealed. Early S2 Jack/Ianto.
Happy dance myself for being able to read it again !
I couldn't have find it on my own as I thought it was the main story and not a part of an other one !
I was searching it for weeks now, it popped in my head and it was driving me mad not to find it !!
It's a really great story !
Yes that's it !
Thank you so much. Does a happy dance :-)