This may sound silly, but I would rather be dumped than do the breaking up. I know, it's ludicrous. But, I am terrible at doing the dumping. The guy either cries or thinks we stand another chance. Never a clean break. Always a little mess. I'm getting better at it, though. Now, they just think I'm cold just because I put the kibosh on the whole "let's still be friends" thing. Whatever.
I understand the difficulty of doing it, finding the right time and circumstance to say, "This isn't working." But, at some point you have to woman up and do it. You can't drag it out, keep telling your friends, "I think this is the week I'll end it." At a certain point, you have to pull the plug, not only for your sake, but his as well. It's the kind thing, the right thing to do. What if you were in a relationship with someone you adored and he knew there wasn't a real future for the two of you, but he kept it going because you are such a nice gal, a good person, and, while there's nothing wrong with you, he just doesn't see the two of you making it in the long run...how would you feel if he dragged it out a month or three or twelve or thirty? You deserve to find the right person for you, and so does he. So, eat your spinach, take a multi-vitamin, have an extra shot of espresso in your latte -- whatever it takes to get your courage up to say, "Babe, we need to talk."