How do i stop online relations?

i have a wonderful girlfriend of 3 months, and i care about her tremendously. but every time im alone in my room i start have online relations to get me off. idk why i cant stop on my own, but i cant. it makes me whenever someone is typing to me. i want to stop this and i have tried for the last 3 months but i always end up going back to these online girls who honestly are prob aren't even who they say they are. im not stupid. but im never going to meet anyone, and i just do it to get off. i dont know if i should seek professional help, but i really need to do something. i tried deleting the sn accounts that i have but i gave out fake email, and birthday so it wont let me change the pword. i tried to change it so i dont know the pword write something in randomly, and i cant delete my account. so i have no clue what to do im always haunted to go online, but i always feel like im cheating after wards and that's not the type of person i want to be even if it is just online. no one would suspect me of doing this. im a very well liked guy in my community, and have a lot of respect that because of this i dont feel like i deserve.