I am lost what to do

I have been with my girl for a while now. We have a great time together. We have our ups and downs like all relationships do. We bicker..argue..but eventually come together and talk. I admit that my communication sucks but she has and remains patient with me. I also admit I messed up I the beginning and I hurt her. I was secretly talking to other women online and she caught me. I lied about it still even is I knew she knew the truth. She did eventually accept and we worked on things. Now I know I can’t control when she “gets over” my betrayal. But she now thinks I am going to hurt her. I truly can see that fear in her. I hate I hurt her like that. I do. She sometimes accuses me of things, and I already know where that comes from. I never accuse her because she honestly doesn’t give me the reason to. She let me meet her mother and I knew that was a big big step for her.
Recently we had an issue and she called me out for it. I told her I was still at work and she knew I normally get off at a certain time. I lied about it. I don’t even know why. I lied to her. I told her I was still working when I wasn’t. I was home. She caught me because when I told her I was now leaving work, she called my phone. In her mind I should be in the car driving and she heard nothing but silence. Other times when I’m driving she knows the sound. She asked me what I was doing and me knowing I’m lying I got defensive. I yelled at her “I’m driving what the heck you men, you want to FaceTime me or something!” I already knew she wasn’t going to FaceTime me. Smh. It was such a small petty argument and I stupidly lied. She got off the phone crying. I’m sure she thinks I was with someone or talking to someone else. I know she knows I lied and I got annoyed. She questioned me and I got annoyed. Please help me what can I do? She cried getting off the phone. This is small but I want my girl. She has a right to accuse me at times, I did that to her I hurt her. I lied to her face on the past. Please help.