RedHighHeels, you can't control your ex-boyfriend's actions in any way, but you can control your own. Don't worry about what he or his current girlfriend has to say about you at all. Sooner or later he will be seen for what he is, and his new girlfriend will certainly have bigger things to worry about than you.
Avoid drama. If anyone asks, just say, "It didn't work out." However, if he touches you or threatens you in any way, it's time to involve your friendly campus police.
Many campuses have a service where a security guard or volunteer will escort you across campus after dark. Take advantage of this. I've known women who have met really great guys this way.
I would like for you to consider taking martial arts training. I studied Aikido for five years. It's very female friendly as it does not rely on size nor strength, and there are no kicks or punches. It's very empowering. And you will meet lots of wonderful guys who are black belts who will become your new "big brothers."