Well, I'm not going to be a killjoy, but I will advise you to be realistic.
If your breakup was a particularly bad one, you might find once you get there that the Disney magic isn't really doing it for you. At the risk of being Mr. Sensitive New Age Guy, I'd tell you to go, but let your feelings dictate what you do. If you're feeling up to hitting the parks, do so. If you're a little depressed and don't think the parks will cheer you up, stay at the hotel, go swimming in the pool. If your hotel has a gym, hit it and work out some aggression. If you get hit with a wave of sadness once you're there, keep some sunglasses handy (good advice anyway with the sun, haha). Worried about eating alone? Bring a book or a CD/MP3 player. Go at your own pace.
If you want to chance either a "hookup" or just spending the day with someone, you can always try going to an online dating service like match.com or nerve.com, and look up people in the Orlando area who list WDW as an interest, who are also interested in just dating (I don't mean no-strings-attached kinkiness, but someone genuinely interested in meeting people). I did that when taking a trip to Londond and met a few cool women that way. But that probably won't be necessary. Though you might not find a lot of people going to WDW solo, you will find people there who are single. Unattached women taking vacations with their parents and/or sibs. Groups of friends going together. And people who are going for the same reason you are. Most people won't be judgmental about you being there alone. In fact, some people might consider you brave, as many folks don't like the idea of being anywhere alone (as evidenced by all the people in my local mall yapping on their cell phones, as if to not have a friend or loved one's voice in your ear constantly is an invitation to despair).
And if someone DOES have the audacity, the unmitigated GALL, to ask why you're there alone, take out a vial filled with grey ashes, and say they're the remains of your wife. She made you swear, ON HER DEATHBED, that you'd scatter some of her ashes in each of the theme parks. Then act like you're barely keeping her composure while talking about how much you miss her. That'll teach them to mind their own business.
