If you've been paying child support this whole time, that's more than most "sperm donors" will do. Let's be honest, if you aren't going to be a positive influence in someone's life, stay the hell out of it. I respect that. Now is not the time to go waltzing back like in some romantic movie. This is real life. If you don't feel it in your heart, you are better off with the status quo. If you happen to have an epiphany, well, that's another story.
Whatever you decide, it's not for me to judge, Asshole (this is the Flame Forum, afterall!)
edit: apparently my brethren are judging :-/