This girl is tryin to lie to my boyfriend to get him to break up wit me?

If i were you i would confront her on her lies in front of him to solve the problem once and for all and then i would talk to him about his trust issues because he should believe your word over hers because you are his girlfriend. And the only reason she is spreading rumors is because she wants him for herself . Don't give her the upper hand expose her once and for all and in the end you will feel so much better.