I have been dishonest

I have been with my gf for 6 months. I used to be a serial dating app person and on instagram liming girls photos commenting and I brought that habit over to our relationship and got caught, this caused trust issues and has only gotten worse since. I have constantly been deciteful and dishonest about my friend talking to me who’s a girl because I thought she would get jealous and deep down I know it’s because I didn’t want to cut my friend off.

However I was caught in my lies multiple times no matter how small and even deleted messages from that said friend, I have looked sketchy and lied about so much and broken so much trust after she has forgiven me multiple times. I have been emotionally immature and learnt so much on how to truly treat someone with love but at the expense of breaking her heart a lot. All I want is to truly show her how much she means to me and that I am so in love with her. I need help and guidance on myself and how to fix this trust issue that seems not to be able to be mended