I can't stop arguing, I could use some help

So I've always been a bit argumentative, I'm not sure why, but I know it's not because of some need to be right all the time. it's not big arguments either it's like stuff that just comes out. example: no that's not when that happened, or her name was Alexis not Alicia. it's always insignificant stuff and I know it's starting to wear on my girlfriend. We're currently trying for our first child. I've bought a ring and plan to propose soon as Well, however I owe it to her to stop this before I can think about asking her to be my wife. any tips or help on how to stop myself would be greatly appreciated. i should mention I also keep a notebook in order to write down different cues for myself that I can try to pick up on and even have given myself a keyword to say in my head during every conversation so I remember to slow down and form a response rather than just blurt it out.