Has it ever crossed Sonic's mind to (politely) ask Amy to back off a little bit? She's made her intentions more than clear, and if she truly adores Sonic, she'll respect him enough to accommodate his wishes.
And this is coming from a Sonamy fan, mind you. I just think that this dynamic, though perhaps only a slight exaggeration of the truth, is hackneyed in Sonic fan art.
What makes is so horrible? I hate it when artists try to bring themselves down. Sure, even if it is a simple sketch that was colored quickly, it isn't "horrible" Come on, man, don't do this to yourself.