Dude, she obviously wants you, or at least a reason to break up with him and try with you. Digging up your number could be something that got her in trouble at work.
She's probably still dependent on this asshole for something, whether it be living arrangements, companionship/friendship, or just fear of being alone. The fact that she told you she wasn't happy is more than what most girls would do. No girl would open up that much to a guy they didn't have an interest in.
Unless she thought he was gay and immediately friend-zoned his ass