Should i confront him about this or brush it off?

I dated a guy who brokeup with me because a relationship is too stressful for him at the moment.. Then he told me he went on a date and told the girl he just wanted to have fun but now she wont leave him alone, im not supposed to pressure him about a relationship and we can be friends, on his facebook she leaves comments like i missed you call sorry and thank you babe and thanx babe your the best... Would you call soneone casual babe? What can i do without puting pressure on him or making him think im crazy but i need to know if i should be threatened by this girl.. Please someone help me! I need him