Okay. Stop. Right there.
It's not terrible. The writing is quite good and the grammar and spelling is also fine. But...
It's very cliché. And the fact that I can tell that by the first chapter is NOT a good thing. Seriously, the whole Gerard loves Frank. Frank loves Gerard. Gerard cheats on Frank. Frank is upset. Gerard cuts himself thing has been done so many times before that I'm actually getting a hangover from counting. It's really not original and it gets very boring very quickly. Sorry to break it to you.
Also the dialogue is slightly...staged. Do you know what I mean? It reads like it belongs in an old 1940's black and white classic starring Ingrid Bergman. Try and use more modern phrases and remember that Gerard and Frank, though they may be gay, are still men. Some of their language is a little feminine.
In a nutshell the dialogue needs work, as does the storyline. I can tell you're a decent writer, though this is the first fic of yours I've read, but it sounds a little like a repeat of a cheesey Frerard romance. Prove me wrong.
Author's response
Thanks for the praise, and yeah, I agree. I felt like doing something really cliche, to get back into the swing of things. Yeah, they do sound staged and feminine, I'm not that great at writing dialogue :s I'll work on the storyline and hopefully I will be able to prove you wrong, and there'll probably be a drastic edit to this chapter. Thanks for your criticism, it's really useful :)