Most Helpful Girl
I don't think you should break it off. Sometimes people are just generally less affectionate, especially when it comes to showing it in public. I don't think that means she cares any less about you, and you shouldn't worry about it.
However everyone loves and shows affection differently, this is their love language. Perhaps you and your partner's love languages do not line up, this doesn't mean it necessarily won't work out, but if it is giving you a complex and causing you to be insecure and unhappy, maybe you should consider finding someone who shares the same love language as you.
Consider other things, such as how she's treated past partners, or if she at one time acted much differently regarding her displays of affection for you. If this is the case, then ask her if she has had a change in heart and tell her that you will be understanding if she has, that way she will feel encouraged to be honest and truthful with you.