STORY FOUND! LINK IN COMMENT
Well, I have a new story I am trying to find, and I hope to have some success with this one, though I have a lot less details than I had for the other one. In fact, I really only remember two things about it, and one of those memories is debatable.
All I really remember for sure is that Tony has been wronged in some way and he goes in to the armor, and for sone reason he tells everyone that hes a decaying . . . I want to say female, but I'm not sure about that detail, and is dieing, due to some lab experiment that Tony saved her from.
I think eventually Peter\Spiderman figures his identity out, but thats the part I'm not sure about.