They've Broken Up

First of all, do you think you'll have enough capital gain to worry about tax on it?  You'll have expenses of selling -- using an agent, for one thing, since you're not down there yourselves, and other expenses of selling. 
At any rate, the homesellers exclusion is meant for people who are making the property their main residence, and you're not.  Even if you waited for the two years, you wouldn't have been occupying the place yourselves.
No point in waiting.  I'd say call a broker down there, call a couple, pick the one who inspires confidence, and get rid of the property.  If you're thinking of renting it out -- or your ex is -- remember that being an absentee landlord is really asking for trouble.