Is My gf/fiancee really committed?

want to know what this mean when everytime I wish my gf/fiancee happy anniversary, she turns it around saying im making her feel bad by saying it every month cause im always remembering it, she says she forgets. when i tell her, she will say it and laugh. it makes me feel like she's not committed, and that shes somewhere else. Let me add, this is same female who cheated and hurt me twice. It just worries me when she acts like this. Help