Hello Sir I Masturbate Since 4 Years And Now I

Hello sir i masturbate since 4 years and now i am 19 year and i have a gf also and i say to that i am addictive of masturbate i promise to her that i never do this practise but after 8 months i started doing this once again please help me i think i cheat my gf i want that i to stop this masturbation will it harmto my future life my penis goes curve shape also was it effect of masturbate pls help me i think i lost my socio ethics