PLEASE DON'T POST ANYTHING ANYMORE. I don't know how to close a forum, but thanks to the support provided below, I realized that not breaking up with him was a waste of my time. So I did. And shockingly, it went over fairly well. I'm glad to say that I'm free, and thank you for your support. DEVIANTART RULES!
Here's a great example of someone doing all the wrong things for everyone but themselves. Ask yourself, whose life is it? Is it your friends? No, so fuck them. Is it anyone's business? No, so fuck them. You don't need to give any reasons to anyone (minus your boyfriend) and if you do, it can damn well be because I feel like it if you want. It's your fucking life, stop living for everyone else.
This same issue carries over to why you can't break up with someone, and be honest about how you feel. You'd rather him be happy in a lie, than to allow yourself to be happy. But this doesn't make things better. Now that you feel like this, the relationship will deteriorate slowly but surely. And all you accomplish by trying to spare him now, is to make things much worse for him later, and for you. You just end up pissing away parts of both your lives because you're too scared of telling the truth. And he'll feel deceived that you've been living a lie to him, and that could have a resounding impact on how he trusts people in the future as well.
If you know it's over, and that is how you feel, than have to conviction, and the respect to be honest and end it as soon as you can. If you really do care about him as a friend still, than the better thing to do is to just end it now.
Break up with him. It's not trolling to tell you to bloody well do it. How would you feel if you found out someone you loved had been faking their feelings and lying to you in return? It would be horrible and not something a friend would do. It might hurt him in the present to deal with a break up, but it will be infinitely better in the long run. Also, definitely do it face to face; it shows you care and aren't trying to weasel out of an awkward conversation.
If your friends ask about it, just be polite about it all and say that you feel like you've grown apart. He's a great guy, but you don't think of him as a boyfriend anymore. Whatever. If they keep pushing, just shrug and say it doesn't always have to be complicated if you're mature about losing feelings for someone.
Two years isn't all that long compared to a lifetime. He'll get over it and eventually thank you for being respectful instead of lying to avoid feeling bad. Doing that (or trying something silly like making him break up with you) would be selfish on your part, trust me.
It'll suck at the time, no one will disagree with that. But future you and your future ex boyfriend will be glad you did it rather than lie about it; all that does it encourage resentment and bitterness.